Colloids and Interfaces doi: 10.3390/colloids10030041

Authors: Anton V. Grivin Il’ya I. Kraynik Daniil A. Kabanov Anna M. Nechaeva Gali D. Markova Eva S. Burmitskaya Anton M. Shulgin Anna V. Andreeva Vasilina A. Zakharova Oleg A. Raitman Svetlana O. Samusenko Irina I. Levina Mikhail V. Motyakin Valerie A. Dyatlov Irina Yu. Gorbunova Inessa A. Gritskova Valeriy P. Meshalkin Yaroslav O. Mezhuev

Branched poly(vinyl alcohol) (PVA) was synthesized via chemical modification of linear PVA with epichlorohydrin in an alkaline aqueous medium under conditions preventing crosslinking. Branching was confirmed by IR and Heteronuclear Single Quantum Coherence (HSQC) spectroscopy, as well as by viscometric analysis. An iterative procedure is proposed for refining the branching factor (g) and the viscosity-average molecular weight of the branched macromolecules. Coil diameters determined by viscometry and dynamic light scattering showed satisfactory agreement. While an increase in the viscosity-average molecular weight of branched PVA enhances its surface activity in the low-adsorption region, the branched geometry itself hinders subsequent adsorption due to steric shielding of the interface. This correlates with wetting behavior on Teflon: lightly branched PVA requires a higher concentration to induce wetting inversion than its linear counterpart but further increase in molecular weight shifts the inversion point to lower concentrations due to a higher density of hydroxyl groups. Concurrently, the concentration dependence of the work of adhesion degenerates with increasing molecular weight. Despite their reduced adsorption capacity, the specific geometry of branched PVA macromolecules provides effective steric stabilization of micrometer-sized particles during styrene suspension polymerization. These results demonstrate that chain branching in PVA is a powerful tool for tuning its adsorption properties, stabilizing ability, and interfacial activity.

Colloids and Interfaces doi: 10.3390/colloids10030040

Authors: Mayu Kakizaki Makoto Hikichi Kotaro Okawa Masatoshi Maeki Manabu Tokeshi Ryota Suzuki Tianle Gao Feng Li Takuya Isono Kenji Tajima Toshifumi Satoh Shin-ichiro Sato Takuya Yamamoto

Dispersion stabilization of nanoparticles for catalytic reactions is an important issue. However, dispersing agents should be carefully selected not to hinder catalytic performance. In the present study, physisorption of cyclic poly(ethylene glycol) (c-PEG) onto platinum nanoparticles (PtNPs) was investigated in comparison with unmodified PtNPs (PtNPs/No PEG), PtNPs mixed with linear PEG (PtNPs/HO-PEG-OH), and PtNPs chemisorbed with HS-PEG-OMe (PtNPs/HS-PEG-OMe). DLS showed a significant increase in the particle size for PtNPs/c-PEG and PtNPs/HS-PEG-OMe compared to PtNPs/No PEG and PtNPs/HO-PEG-OH. ζ-potential measurements revealed values around −30 mV for PtNPs/No PEG and PtNPs/HO-PEG-OH, whereas PtNPs/c-PEG and PtNPs/HS-PEG-OMe approached 0 mV, which indicated that c-PEG and HS-PEG-OMe adsorb onto PtNPs to form a shielding layer. Moreover, PtNPs/c-PEG and PtNPs/HS-PEG-OMe were stable in a phosphate-buffered saline (PBS) solution, but PtNPs/No PEG and PtNPs/HO-PEG-OH immediately aggregated. This suggests that high dispersion stability by c-PEG is comparable to ordinary surface modification using HS-PEG-OMe. Furthermore, the catalytic ability of PtNPs/c-PEG and PtNPs/HS-PEG-OMe was compared in various reactions. As a result, physisorbed PtNPs/c-PEG showed suitable catalytic activities, whereas chemisorbed PtNPs/HS-PEG-OMe was significantly hampered by the blocking of the catalytic sites with thiol in some reactions. Thus, physisorption of c-PEG endows PtNPs with dispersion stability and maintains the catalytic ability, leading to an alternative way of modifying metal nanoparticles.

Colloids and Interfaces doi: 10.3390/colloids10030039

Authors: Akmal Nazir Plamen Tchoukov

From a colloid science perspective, colloidal systems are not simply heterogeneous mixtures, but organized dispersed media in which solid particles, liquid droplets, gas bubbles, or other mesoscopic entities are distributed within a continuous phase [...]

Colloids and Interfaces doi: 10.3390/colloids10030038

Authors: Rajinder Pal

The rheology of dilute emulsions is reviewed comprehensively. The fundamental equations governing the flow fields inside and outside the droplets are discussed, along with the boundary conditions. The rheological constitutive law for dilute emulsions with pure interfaces characterized by interfacial tension is developed using the flow field external to the droplets. Both zero-order and first-order deformations of droplets are considered. Dilute emulsions exhibit non-Newtonian behavior. The influences of surface charge and surfactants on the emulsion rheology are covered in detail. The rheology of emulsions of double droplets and droplets covered with elastic membranes is covered as well. Finally, a significant section of the review is focused on the dynamic rheology of dilute emulsions. Emulsions with pure interfaces and additive-laden interfaces are considered. The theories developed for the dynamic rheology of emulsions consisting of different types of interfaces are reviewed, including purely viscous interfaces, purely elastic interfaces, viscoelastic interfaces, and interfaces possessing bending rigidity. In general, the theory for dilute emulsion rheology is well developed. Our current understanding of dilute emulsion rheology is good from a theoretical point of view. A priori predictions of dilute emulsion rheology are possible using the existing theories. However, serious gaps in the existing knowledge on dilute emulsion rheology remain. This review identifies the gaps in existing knowledge and points out future directions in research related to dilute emulsion rheology.

Colloids and Interfaces doi: 10.3390/colloids10030037

Authors: Janaina Lima Yasmin Diniz de Morais Lidiane Fernandes Rogério Andrade Leonardo Batista Ana M. Sarinho Maria Eduarda Costa Renata Duarte Almeida Hugo M. Lisboa

Gum arabic (GA) is a widely used natural hydrocolloid in food processing because its protein–polysaccharide architecture combines high water solubility, low bulk viscosity, and useful interfacial activity. These attributes make GA valuable as an emulsifier, encapsulating agent, and film-forming material, but native GA is constrained by source-dependent heterogeneity, limited antioxidant functionality, relatively high dosage requirements in some emulsions, and modest barrier and mechanical performance in dried matrices. This review synthesizes recent advances in chemical functionalization, enzymatic and oxidative grafting, physical fractionation and complexation, and Maillard-type bioconjugation as routes to tailor GA for food engineering applications. Emphasis is placed on process-relevant structure–property relationships, including dynamic adsorption, interfacial rheology, emulsifying and encapsulation efficiency, bulk rheology, powder glass transition and hygroscopicity, film barrier behavior, and release kinetics. Across beverage emulsions, spray-dried powders, coacervates, coatings, and delivery systems, the evidence shows that modification must be selected according to the dominant process bottleneck, such as adsorption kinetics, oxidative stability, drying behavior, or humidity-sensitive matrix mobility. This review also identifies priorities for translation, including model-ready measurements, the management of raw-material variability, scale-up-aware processing, and sustainability and regulatory practicality. Overall, modified GA emerges as a versatile platform for designing more robust, application-specific food colloids, encapsulates, and functional coatings.

Colloids and Interfaces doi: 10.3390/colloids10030036

Authors: Ramonna I. Kosheleva Agni A. Moutzouroglou George Z. Kyzas Athanasios Mitropoulos

The temporal dynamics and statistical properties of air nanobubbles (NBs) in ultrapure water were investigated using nanoparticle tracking analysis (NTA). Statistical analysis of NB lifetimes reveals a strong correlation between bubble size and persistence. The mean bubble diameter increases rapidly from ~100 nm for short-lived detections to a characteristic size of about 500 nm for bubbles surviving longer than 40 frames, after which the size remains approximately constant. The population of detected NBs decreases monotonically with increasing lifetime, approximately following an exponential decay. Temporal analysis of the cumulative population yields a scaling exponent of ~0.6, indicating correlated fluctuations rather than independent stochastic events. Spatial observations confirm that NBs are separated by micrometer-scale distances, excluding direct bubble–bubble interactions. The combined statistical and imaging results support a picture in which NBs behave as dynamically coupled gas domains embedded within localized dissolved-gas microenvironments. The observed non-monotonic population dynamics cannot be explained by irreversible dissolution alone. Instead, the data indicate that NBs undergo continuous cycles of dissolution and replenishment. Within this framework, localized gas micro-domains, potentially exhibiting non-extensive behaviour, evolve dynamically and act as transient reservoirs. Upon bubble disappearance, these regions persist and diffuse, while their interaction may locally restore conditions for nucleation. This mechanism provides a physically consistent explanation for the observed cyclic behaviour and the apparent persistence of NBs beyond classical predictions.

Colloids and Interfaces doi: 10.3390/colloids10030035

Authors: Shanshan Zeng Yun Chen Wentong Chen Jing Wang Yunlin Zeng Yong Cao Yunjiao Chen

Cyclocarya paliurus polysaccharides (CPP) possess various physiological functions such as lipid-lowering and antioxidant activities. However, as a complex plant-based dispersion system, the interfacial characteristics of fermented C. paliurus beverages often restrict the release of bioefficacy of the active ingredients. This study investigated the impact of particle size on the colloidal stability and lipid-lowering activity of C. paliurus beverages fermented by Lactobacillus plantarum and established an empirical correlation between the two. While the 200–300 mesh fraction showed superior physical stability, the 40–60 mesh fraction was identified as the optimal formulation in this study when balancing ROS indicators. In vivo assays using Caenorhabditis elegans demonstrated that the 40–60 mesh formulation significantly reduced MDA levels and inhibited lipid accumulation, decreasing TG content by 19–46%. Notably, the average diameter of lipid droplets decreased by 38.4%, promoting the conversion of large storage-type droplets to small/medium-sized droplets with high metabolic activity. This study reveals the trade-off between physical dispersibility and bioavailability, providing a theoretical basis for optimizing the interfacial structure of functional plant-based beverages.

Colloids and Interfaces doi: 10.3390/colloids10030034

Authors: To Ngai Xiuying Qiao

This Special Issue brings together a diverse collection of contributions that highlight the rapid advances and emerging directions in colloid and interface science across Asia [...]

Colloids and Interfaces doi: 10.3390/colloids10030033

Authors: Emilia Świątek Jan Taudul Daria Kępińska Dorota Nieciecka Paweł Krysiński

Cannabinol (CBN) is a highly lipophilic phytocannabinoid whose biomedical application is limited by poor water solubility. In this study, colloidal hydroxyapatite nanoparticles (nHAp) were evaluated as a carrier for CBN, and their effect on model lipid membranes was investigated. Interactions between CBN and lipids were examined using Langmuir monolayers and lipid bilayers (black lipid membranes, BLMs). Langmuir monolayer studies revealed strong interactions between CBN and lipids, resulting in changes in isotherms, compressibility, and monolayer stability. BLM measurements indicated that delivery of CBN via nHAp modifies the electrical properties and stability of the lipid bilayer, suggesting alterations in membrane organization and permeability. These results demonstrate that hydroxyapatite nanoparticles can effectively serve as a carrier for cannabinol while modulating its interactions with lipid membranes.

Colloids and Interfaces doi: 10.3390/colloids10020032

Authors: Volodymyr I. Kovalchuk Eugene V. Aksenenko

From a physical point of view, interfaces are not simply borders between two contacting continuous phases, but material objects with specific properties [...]

Colloids and Interfaces doi: 10.3390/colloids10020031

Authors: Linwei Yang Jia Liu He Wang Xiaoyun Yi Zhi Dang

The colloidal particles present in natural soil and groundwater systems possess distinctive properties that enable them to migrate across solid surfaces, thereby exerting a significant influence on the distribution of pollutants. While the attachment of colloidal particles to solid surfaces has been extensively investigated, the mechanisms governing their detachment under varying hydrochemical conditions remain largely unexplored. The common interaction between montmorillonite colloids and solid medium (Al2O3) in soil affects the fate of pollutants such as heavy metals. In our study, Al2O3 was used as solid medium to observe the adsorption and desorption behavior of montmorillonite colloids. It was found that the adsorption capacity of Al2O3 to montmorillonite colloids could reach 4.71 mg g−1 (pH 5.0 and 10 mM NaCl concentration). X-ray photoelectron spectroscopy analysis shows that montmorillonite colloids react with the Al2O3 surface mainly through chemical groups with –O–Si bonds. Desorption experiments show that SDS drives desorption by neutralizing and reversing the surface charge of Al2O3, while CTAB directly modifies montmorillonite colloids and introduces steric hindrance to achieve desorption. These research data contribute to a comprehensive understanding of the migration behavior of montmorillonite colloids on solid phases.

Colloids and Interfaces doi: 10.3390/colloids10020030

Authors: Abdulmajeed Murad Arne Skauge Tormod Skauge

Polymer flooding is a well-established chemical enhanced oil recovery (EOR) method, primarily aimed at improving sweep efficiency. However, the interplay between polymer properties and porous media, particularly the influence on permeability reduction, remains poorly understood. In this study, we investigate how polymer molecular weight, chemistry, and mechanical pre-shearing influence residual resistance factor (RRF) and in situ rheology in Berea sandstone core floods. Post-polymer brine flow exhibits clear non-Darcy behavior, indicating that permeability becomes rate-dependent after polymer adsorption. Application of a Forchheimer-based approach demonstrates that inertial contributions become significant at reservoir-relevant velocities, suggesting enhanced microscopic inertia dissipation associated with interaction between flowing brine and the stationary adsorbed polymer layer. Applying conventional Darcy-based interpretation systematically overestimates RRF under these conditions. RRF increases with polymer molecular weight for polymers with similar bulk viscosities, suggesting that permeability reduction is primarily controlled by effective hydrodynamic size and pore-scale interactions rather than polymer concentration. Mechanical pre-shearing substantially reduces RRF and the non-linear flow contribution, suggesting that laboratory measurements performed on unsheared solutions may overestimate field-scale injectivity impairment. In contrast, an ATBS-containing polymer exhibits relatively low RRF but high apparent viscosity, indicating that alterations in polymer chemistry may override molecular weight as the main factor. The results demonstrate that polymer–surface interactions can induce rate-dependent permeability at reservoir-relevant velocities, and highlight the need for non-Darcy analysis when interpreting polymer core flood experiments for field application.

Colloids and Interfaces doi: 10.3390/colloids10020029

Authors: Michela Elena Pedretti Libero Liggieri Luca Valentini Giovanna Canu Alberto Lagazzo Francesca Ravera Eva Santini

Robust, lightweight, and thermally insulating building materials, developed according to the In Situ Resource Utilization (ISRU) paradigm, are essential for enabling Moon settlements. With this aim, we have investigated the formulation and characterization of porous geopolymeric materials based on a lunar regolith simulant, focusing on the influence of surfactants and rheology-modifying additives on pore structure and final material performance. As an optimized procedure, a pre-formed TTAB foam was, in fact, incorporated into the geopolymeric precursor slurries to achieve a suitable porosity. Then, the effects of three thickeners (xanthan gum, bentonite, and Actigel-208) were evaluated in view of the possible utilization for the production of building blocks by 3D printing. Observations of the pore structure after the geopolymeric consolidation of the slurries showed predominantly closed-cell networks across all formulations, with a pore morphology strongly dependent on the thickener used. Xanthan gum promoted high porosity but reduced mechanical integrity, whereas bentonite produced denser structures with higher thermal conductivity. Actigel-208 provided the most balanced performance, combining adequate porosity with improved strength. These findings demonstrate the potential of producing thermally insulating, structurally stable solid foams from lunar regolith simulants via a geopolymerization route.

Colloids and Interfaces doi: 10.3390/colloids10020028

Authors: Rajinder Pal

Non-dilute emulsions are emulsions where the concentration of the droplets is high enough for the neighbouring droplets to interact with each other hydrodynamically but is still smaller than the packed bed concentration where the droplets are packed and deformed against each other. Thus, they cover a broad range of droplet concentrations. Many emulsions encountered in industrial applications fall under this category. Non-dilute emulsions exhibit rich rheological behaviour, from a simple Newtonian fluid to a highly non-Newtonian fluid, reflecting shear-thinning, shear-thickening, yield stress, viscoelasticity, etc. In this article, the rheology of non-dilute emulsions is reviewed comprehensively. Emulsions of hard-sphere-type droplets and deformable droplets, with and without surfactants, are covered. The mathematical models describing the rheological behaviour of non-dilute emulsions are discussed. The influences of electric charge and interfacial rheology on the rheological behaviour of emulsions are covered in detail. The flocculation of droplets caused by different mechanisms, such as depletion and bridging induced by additives, and their effect on emulsion rheology are investigated thoroughly. Finally, the dynamic rheology of non-dilute emulsions is discussed, covering both pure oil–water interfaces and additive-laden interfaces. The mathematical models describing the dynamic rheological behaviour of non-dilute emulsions are described. Based on the existing theoretical and empirical models, it is possible to a priori predict the rheology of non-dilute emulsions. However, serious gaps in the existing knowledge on non-dilute emulsion rheology remain. This review identifies the gaps in existing knowledge and points out future directions in research related to non-dilute emulsion rheology.

Colloids and Interfaces doi: 10.3390/colloids10020027

Authors: Jielin Liu Qiang Li Lingxin Wang Jinlong Zha Lu Gao Siyu Sheng Wanmei Liu Yuzhen Ning Zhihong Zhao Kesong Liu Lei Jiang

The acquisition of liquid energy sources and basic chemicals from washing water via Kolbe electrolysis is of great significance for achieving the goal of carbon-neutrality. However, oleophilic products tend to adhere to the platinum (Pt) electrode, which results in a shortened working life for Kolbe electrolysis. To address these issues, a novel method for endowing carbon fiber paper electrodes with underwater superoleophobic properties through simple electrodeposition is reported herein. The underwater superoleophobic electrodes improve the efficiency of the Kolbe electrolysis reaction, as oleophilic products can be easily removed from the electrode surface, thereby exposing more active reaction sites. Importantly, the underwater superoleophobic electrodes have fully demonstrated their capability of excellent electrochemical performance, stability, and durability. This work provides a novel approach for the design of high-performance electrodes in organic electro-catalysis.

Colloids and Interfaces doi: 10.3390/colloids10020026

Authors: Veton Haziri Avni Berisha Klemen Bohinc

The dangerous potential of chemical warfare requires immediate development of new materials capable of detecting and efficiently adsorbing the toxic nerve agents VX and Novichok (A-234). The current adsorbents fail to achieve sufficient detection efficiency and specific binding capabilities. Our research, conducted through advanced computational modeling, predicts that carbon nanocones (CNCs) could function as effective molecular traps for these toxic substances. The research combines density functional theory (DFT) with molecular dynamics (MD) and Monte Carlo (MC) simulations to explain the basic principles of molecular trapping by these agents. The nanocone shape produces two distinct and selective binding areas. MC shows preferential trapping VX molecules within the internal concave surface (P1), while A-234 molecules are strongly adsorbed on the external convex surface (P2). Docking results complement this by showing that A-234 exhibits stronger single-molecule binding on the more open surface, consistent with its preference for P2. The nanocone captures molecules through van der Waals forces, which produce measurable electronic changes that modify its electronic signature. The research demonstrates that carbon nanocones represent a promising candidate material for the future development of chemical defense systems, potentially including sensitive detection systems and advanced filtration technologies.

Colloids and Interfaces doi: 10.3390/colloids10020025

Authors: Ángela Sánchez-García Francisco Ortega Ramón G. Rubio Eduardo Guzmán

Liposomes are widely recognized as versatile nanocarriers in drug delivery due to their biocompatibility, tunable physicochemical properties, and ability to incorporate both hydrophilic and hydrophobic compounds. In this study, the encapsulation and release of diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), using lecithin–cholesterol liposomes are explored. Encapsulation parameters were first optimized with calcein as a model fluorophore, confirming that cholesterol addition enhances encapsulation efficiency by reducing membrane permeability. Guided by these results, liposomes containing equal weight fractions of lecithin and cholesterol were selected as an optimized formulation, providing calcein and diclofenac encapsulation efficiencies up to approximately 35% while maintaining hydrodynamic diameters below 300 nm with low polydispersity (PdI < 0.2), optimal for intravenous administration and prolonged systemic circulation. Release studies demonstrated sustained drug release over 15 days, with cumulative release exceeding 80%. Weibull modeling yielded θ∞ ≈ 1 and β values up to ~1.6 at higher loadings, with β > 1 indicating a complex, sigmoidal (non-Fickian) release mechanism. These findings support the potential of liposomes as delivery platforms for NSAIDs with solubility and bioavailability limitations.

Colloids and Interfaces doi: 10.3390/colloids10020024

Authors: Azren Aida Asmawi Nur Ain Izzati Mohd Zainudin Nurul Aini Mohd Azman Fatmawati Adam Nurul Farhana Ahmad Aljafree Mohamad Firdaus Ahmad Mohd Basyaruddin Abdul Rahman

Palm oil is a major agricultural commodity and an important economic driver in Asia. However, the sustainability and productivity of this crop are constantly threatened by a range of pathogenic fungi, especially Ganoderma boninense. Therefore, this study aimed to develop an eco-friendly hexaconazole-loaded nanoemulsion (Hexa-NE) for effective and targeted fungicide delivery while reducing environmental and health impacts. The optimized Hexa-NE formulation was evaluated for particle size, polydispersity index (PDI), zeta potential, pH, viscosity, and morphology using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Fungicide release, stability, and antifungal activity were conducted to assess the overall efficacy and performance of the formulation. The Hexa-NE exhibited particle size of 105.8 nm, a PDI of 0.358, a zeta potential of −53.53 mV. The formulation remained stable over three months of storage. It also demonstrated favourable physicochemical properties including low viscosity (30.24 mPa·s), low surface tension (23.87 mN/m), and suitable pH (6.14) for foliar application. TEM and SEM analyses confirmed spherical droplets and revealed significant hyphal damage to G. boninense. The antifungal test showed a higher inhibition of 97.1% at 0.1 µM of Hexa-NE as compared to hexaconazole solution which only 40% at the same concentration. Release studies exhibited a sustained release of hexaconazole, which may prolonged fungicidal activity. In conclusion, Hexa-NE showed promising laboratory-scale antifungal performance against G. boninense. These findings support its potential for further investigation as a nanoformulated fungicide for future greenhouse and field evaluations.

Colloids and Interfaces doi: 10.3390/colloids10010023

Authors: Dmitry Chertin Natalia Gavrilova Ilya Zavidovskiy Maria Myachina Alexander Syuy Victor Nazarov

High-purity precursors are often required for the targeted synthesis of functional nanomaterials. Molybdenum blue (MB) dispersions are promising precursors for the production of functional materials based on molybdenum oxides and carbides. Here, a facile, spectator-ion-free synthesis of molybdenum blue dispersions via a tailored ion-exchange strategy is reported. By eliminating extrinsic counter-ions, we achieve uniform toroidal nanoclusters (~3.5 nm) of {Mo154} wheel-type molybdenum blue with a precise mixed-valence Mo5+/Mo6+ framework and long time aggregative and sedimentation stability. Moderate reduction ratios yield crystalline monoclinic MoO2, whereas high reduction ratios drive an in situ carbothermal reduction, selectively yielding hexagonal β-Mo2C/η-MoC phases. This approach establishes a versatile, scalable pathway for engineering molybdenum blue nanoparticles as precursors for oxide- and carbide-based advanced functional materials.

Colloids and Interfaces doi: 10.3390/colloids10010022

Authors: Elodie Melro Marta L. Correia Carolina F. Jesus Andreia A. S. Alves Filipe E. Antunes Margarida Lindo Daniel Ribeiro

Gum arabic (GA) is a promising polymer for oil microencapsulation due to its emulsifying and film-forming properties and regulatory acceptance. Here we introduce a fully natural, low-energy emulsion–freeze-drying route and a head-to-head screening framework that compares surfactant chemistry and oil identity under identical processing conditions. Rice oil was used as a model to evaluate two oil:GA ratios (1:3 and 1:0.3, solid basis) and three surfactants (Tween 80, sodium cocoyl glutamate (SCG), and lecithin) at 0.1–1%. Emulsions were characterized by Dynamic Light Scattering (DLS) (z-average, PDI), emulsification index, and viscosity, then freeze-dried and evaluated for encapsulation efficiency (EE). High oil load (1:0.3) gave EE = 0% for all conditions, whereas GA-rich emulsions (1:3) enabled encapsulation, with 0.1% surfactant selected as optimal. Using this formulation window, six oils (rice, jojoba, aloe vera, sweet almond, safflower, sesame) were screened, yielding EE values from 0 to 95%. Safflower and sesame showed high EE without surfactant, while rice, sweet almond, aloe vera, and jojoba benefited mainly from SCG or lecithin. Despite producing smaller droplets, Tween 80 generated polydisperse, low-stability emulsions and did not improve EE. Overall, EE is governed by GA–surfactant interfacial cohesion and oil chemistry rather than droplet size alone.

Colloids and Interfaces doi: 10.3390/colloids10010021

Authors: Ayşe Selen Yildirim Özlem Erdal Altintaş

The oral delivery of polyphenolic compounds such as rosmarinic acid (Ros) is limited by poor gastrointestinal stability and early release, resulting in low bioaccessibility. Herein, carboxymethylated guar gum (cmGG)-based nanoparticles were developed as a pH-responsive colloidal delivery system to enhance Ros stability, prevent early release, and improve intestinal bioaccessibility. In this context, pH-responsiveness refers to pH-dependent modulation of degradation, and stabilization along the gastrointestinal tract, rather than an abrupt pH-triggered burst release. Guar gum was chemically modified to different degrees of carboxymethylation to enhance its colloidal stability under gastrointestinal conditions, reduce polymer degradation, and enable a more controlled release of the phenolic compound Ros. Comparative evaluation of cmGG systems with varying degrees of carboxymethylation revealed that nanoparticles prepared from highly substituted cmGG exhibited superior colloidal stability and acid resistance, contributing to effective protection of Ros under gastric conditions. Ros-loaded guar gum nanoparticles effectively suppressed release at acidic pH while enabling controlled and sustained release at intestinal pH. Simulated gastrointestinal digestion studies demonstrated that Ros-loaded carboxymethylated guar gum nanoparticles significantly enhanced the gastrointestinal stability and bioaccessibility of Ros compared with non-carboxymethylated guar gum nanoparticles. Overall, these findings indicate that the degree of carboxymethylation is a critical design parameter for tuning colloidal behavior and release performance under the varying pH conditions encountered throughout the gastrointestinal tract in guar gum-based nanoparticle systems.

Colloids and Interfaces doi: 10.3390/colloids10010020

Authors: Costanza Bonnici Maria Federica Marchesi Ester Grilli Marijana Dragosavac

Thyme oil (TO) is emerging as a promising candidate to counteract antimicrobial resistance due to its renowned antimicrobial and anti-inflammatory properties. However, rapid gastric absorption of its bioactive compounds limits its intestinal delivery, where its action is required, so the protection of these components is necessary. This pilot study optimized TO-loaded emulsions for targeted intestinal release. High-shear homogenization and membrane emulsification were compared to formulate single oil in water (O/W) and double water in oil in water (W/O/W) emulsions, screening emulsifiers (lecithin, Tween 20, Tween 80) and functional biopolymers (pectin, sodium alginate). High-shear homogenization with lecithin (0.5%), pectin (1.80%), and sodium alginate (0.2%) yielded stable submicron O/W emulsion (Span = 0.5; d(v,0.5) = 0.21 µm), achieving electrostatic stabilization (ζ-potential = −51.5 ± 1.5 mV) at a target poultry dosage. A pH-responsive behavior was observed: protective hydrogel formed in gastric conditions (d(v,0.5) = 2.64 µm) and maintained stability at intestinal pH (d(v,0.5) = 3.03 µm). Membrane emulsification enabled precise droplet control under mild conditions, producing monodisperse O/W emulsions (d(v,0.5) = 38–59 µm; Span ≤ 1.0) and W/O/W double emulsions (d(v,0.5) = 26.5 µm; Span = 0.6) with ultra-low interfacial tension (0.52 mN·m−1). Repeated membrane passes reduced droplet size to ~6.6 µm. These systems represent a foundational step toward bioactive intestinal delivery, providing a viable antibiotic-free strategy for sustainable livestock production.

Colloids and Interfaces doi: 10.3390/colloids10010019

Authors: Tomislav Vukovic Thomas Luxbacher Jostein Røstad Umer Farooq Ole Torsæter Antje van der Net

Wettability determination is of crucial importance for multiphase flow in porous media. Currently available methods are either applied to simplified geometries (sessile drop) or are time-consuming (Amott, USBM) and cost-intensive (micro-CT scanning). The purpose of this study is to systematically test the streaming potential method as a fast, cheap, and in situ applicable method for surface probing and determination of the wetting state of soda lime glass beads through zeta potential. Different wetting states are achieved by means of silanization and are characterized by an average contact angle. Comparison of contact angles measured by sessile drop on plate geometries and contact angles derived from bead pack micro-CT images confirmed that the treatment is transferable to the bead packs. The correlation between the zeta potential of the single bead size packing with a single wetting state and the contact angle is non-unique over the entire range of tested treatment volume ratios. The contact angle plateaus at higher degrees of silanization, while the zeta potential values still change. Before the plateau, a correlation between contact angle and zeta potential is present. Zeta potential measurements on the mixtures of the same-sized beads with two different wetting states confirm the existing theory that the apparent zeta potential is a surface area-weighted average of constituents. For a mixture where the zeta potential is size dependent, a new correlation for a dual bead system was derived. The non-unique correlation between zeta potential and contact angle, combined with a bead size-dependent zeta potential, will limit the use of zeta potential for contact angle derivation for the system of soda lime glass beads with various silanization coatings used here. Monitoring relative changes of wetting conditions might still be possible.

Colloids and Interfaces doi: 10.3390/colloids10010018

Authors: Diana Abril Liudis L. Pino-Ramos V. Felipe Laurie Ricardo I. Castro Gustavo Cabrera-Barjas Alfredo Pereira Evandra L. Parra Adolfo Marican Esteban F. Durán-Lara Oscar Valdés

In this preliminary study, chitosan-based molecularly imprinted polymers crosslinked with glutaraldehyde were synthesized and evaluated for the selective removal of m-cresol, a volatile phenol associated with the sensory defect known as smoke taint in wine. Three formulations of chitosan-based molecularly imprinted polymers (MIP-Gs) were synthesized using glutaraldehyde as a crosslinker and m-cresol as a template. Non-imprinted polymers (NIP-Gs) served as controls. The polymers were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy, which confirmed successful crosslinking and structural differences between MIPs and NIPs. Adsorption performance was evaluated using solid-phase extraction cartridges packed with the synthesized polymers, employing a Cabernet Sauvignon wine. The MIPs exhibited higher adsorption efficiency and selectivity toward m-cresol compared to NIPs, achieving removal rates of 15% to 40%, depending on polymer formulation and analyte concentration. Molecular dynamics simulations were used to investigate polymer–analyte interactions at the molecular level, providing mechanistic insight into the preferential binding of m-cresol within the imprinted cavities. Physicochemical analyses of red wine showed that m-cresol removal occurred with minimal impact on key phenolic parameters, supporting the functional selectivity of MIPs. These results demonstrate that chitosan-based MIPs constitute a promising class of materials for selective adsorption applications in complex liquid systems.

Colloids and Interfaces doi: 10.3390/colloids10010017

Authors: Ke Zhu Bingjie Meng Ziying Ren Xing Tian Yonglei Xing

Herein, a cobalt–molybdenum bimetallic oxide precursor was synthesized via a hydrothermal route, followed by a phosphidation strategy in a tube furnace to produce a CoMoP cocatalyst. Subsequently, a CoMoP/BiVO4 composite photoanode was successfully constructed by loading the CoMoP cocatalyst onto the surface of an electrodeposited BiVO4 film using a drop-casting method. A suite of analytical tools such as TEM, XRD, and XPS was utilized to comprehensively examine the material morphology and crystalline features, verifying that CoMoP was effectively anchored on the BiVO4 surface with intimate interfacial contact. Photoelectrochemical (PEC) performance testing indicated that the composite photoanode achieved optimal performance with a 200 µL loading of the CoMoP dispersion (2 mg/mL). Under front-side illumination, the photocurrent density of the CoMoP/BiVO4 composite photoelectrode reached a photocurrent density of 2.8 mA/cm2 at 1.23 V (vs. RHE), which is approximately 3.1 times higher than that of unmodified BiVO4 (0.9 mA/cm2). Under back-side illumination, the composite photoanode generated 3.5 mA/cm2, representing a 2.3-fold improvement over the 1.5 mA/cm2 recorded for bare BiVO4. The bandgap energy of BiVO4 was determined to be approximately 2.44 eV based on UV–vis absorption spectra and the corresponding Tauc plot. Owing to its metallic nature, CoMoP exhibits strong broadband absorption in the visible-light region and does not display an intrinsic semiconductor bandgap behavior. Combined with photoluminescence (PL) spectroscopy and PEC results, it was demonstrated that the CoMoP loading effectively promoted interfacial charge separation and transport while accelerating water oxidation kinetics. These results demonstrate that the CoMoP/BiVO4 system serves as an advanced semiconductor material with excellent performance for photoelectrocatalytic water splitting.

Colloids and Interfaces doi: 10.3390/colloids10010016

Authors: Khaleda C. Rinee Jan Ilavsky Ivan Kuzmenco Xiaobing Zuo Amy Y. Xu

Adjuvants are chemical substances used in vaccines to enhance immunogenicity. Among them, aluminum-based nanoparticles are some of the oldest and most widely employed adjuvants in vaccine formulations. A key function of aluminum adjuvants is thought to involve acting as an antigen depot, enabling slow antigen release and providing sufficient time for effective immune activation. Therefore, understanding antigen–adjuvant interactions is essential, as these interactions influence antigen stability, release kinetics, and overall vaccine performance. In this study, we investigated how the physicochemical properties of aluminum hydroxide nanoparticles modulate antigen–protein interactions and affect protein stability. Nanoparticles synthesized under acidic (pH ≈ 5.0) to near-neutral (pH ≈ 7.1) conditions exhibited lower crystallinity, reduced hydroxyl density, and higher interfacial hydration, whereas those prepared under basic conditions (pH ≈ 9.0) displayed increased crystallinity, enriched surface hydroxyl groups, and markedly reduced hydration. Antigen proteins bound to low-crystallinity aluminum hydroxide nanoparticles showed improved thermal stability, while those associated with highly crystalline nanoparticles exhibited reduced thermal stability. Complementary ITC study further suggests that these stability differences are accompanied by changes in their interaction behavior. These findings indicate that the structural and interfacial properties of aluminum hydroxide nanoparticles strongly influence their interactions with antigen proteins and the resulting physical stability. Together, our results demonstrate that the balance among crystallinity, hydroxyl organization, and interfacial hydration governs the thermal behavior of antigen proteins adsorbed onto aluminum hydroxide. This work provides a rational design principle for engineering aluminum-based adjuvants that optimize antigen–protein stability in vaccine formulations.

Colloids and Interfaces doi: 10.3390/colloids10010015

Authors: Ryuse Sakurai Haruka Takenaka Hiroyuki Ogino Takashi Ishiyama Issei Takeuchi Akiyoshi Saitoh

This study aimed to evaluate the feasibility and safety of pulsed-current iontophoresis (IP) for the transdermal delivery of teriparatide, a therapeutic peptide for osteoporosis. Female rats were subjected to in vivo iontophoretic administration under constant or pulsed-current conditions. Serum teriparatide concentrations, skin irritation scores, and transepidermal water loss (TEWL) were assessed. After 2 h of IP, serum teriparatide concentrations reached 53.3 ± 4.0 pg/mL with pulsed current and 48.8 ± 12.6 pg/mL with constant current, confirming successful transdermal absorption of teriparatide (≈4 kDa) into systemic circulation. Skin irritation was significantly reduced under pulsed-current conditions, as indicated by lower erythema, edema, and TEWL values, despite identical total current exposure. These results suggest that intermittent current application during pulsed-current IP alleviates local electrical stress through partial depolarization and may provide a delivery efficiency comparable to that of constant direct current IP while improving tolerability. Overall, pulsed-current IP enables noninvasive and effective systemic delivery of peptide drugs with minimized skin irritation, representing a promising alternative to injection-based administration for macromolecular therapeutics.

Colloids and Interfaces doi: 10.3390/colloids10010014

Authors: Akmal Nazir Reem Zapin Raneem Abudayeh Asma Obaid Hamdan Alkaabi Anuj Niroula Khaja Mohteshamuddin Nayef Ghasem

This study investigated heat-induced protein aggregation in skim camel milk by monitoring changes in the volume-weighted mean particle size (d4,3) during isothermal heating (60–90 °C, up to 60 min, four temperature levels and 25 time–temperature conditions). Pronounced increases in d4,3 with both time and temperature confirmed significant thermal aggregation. The reaction kinetics were described using a generalized exponential growth model, which fitted well at intermediate temperatures (e.g., coefficient of determination (R2) = 0.901 at 70 °C and 0.959 at 80 °C) but deviated at the lower (60 °C) and upper (90 °C) extremes, reflecting more complex behavior. Arrhenius analysis of the rate constant yielded an activation energy of 50.61 kJ mol−1, lower than values typically reported for bovine milk systems, indicating that camel milk proteins require less thermal input to aggregate. In parallel, a machine learning model implemented as an artificial neural network (ANN) predicted d4,3 from time-temperature inputs with high accuracy (R2 > 0.97 across training, validation, and testing), capturing nonlinear patterns without mechanistic assumptions. Together, the kinetic and ANN approaches provide complementary insights into the heat sensitivity of camel milk proteins and offer predictive tools to support the optimization of thermal processing, formulation, and quality control in dairy applications.

Colloids and Interfaces doi: 10.3390/colloids10010013

Authors: Xiuying Qiao Reinhard Miller Emanuel Schneck Kang Sun

Due to its amphiphilicity, the natural fibrous structural protein, silk fibroin (SF), can adsorb at the oil/water interface, form protective viscoelastic layers, and stabilize emulsions. Biocompatible SF-stabilized emulsions can be used in different fields of cosmetics, food, drug delivery, and biomedicine. Depending on the silk processing method, various emulsion types can be obtained, such as film-stabilized emulsions stabilized by SF molecules and Pickering emulsions stabilized by nanostructured SF or SF particles. Nanostructured SF and SF particles, with β-sheet dominated secondary structures, can overcome the drawback of SF molecules with unstable conformation transition during application, and thus endow higher emulsion stability than SF molecules. The emulsions stabilized by SF nanoparticles can endure heat and high ionic strength, while the emulsions stabilized by SF nanofibers show superior stability at high temperature, high salinity, and low pH due to the strong interfacial entangled nanofiber networks. In this review, the recent progress in research on SF-stabilized emulsions is summarized and generalized, including a systematic comparison of the stabilization mechanisms for different SF morphologies, and the influences of the emulsion fabrication technique, component type and proportions, and environmental conditions on the microstructures and properties of SF-stabilized emulsions. Understanding the stabilization mechanism and factors influencing the emulsion stability is of great significance for the design, preparation and application of SF-stabilized emulsions.

Colloids and Interfaces doi: 10.3390/colloids10010012

Authors: Bárbara A. B. dos Santos Rafael E. G. Leal Ana P. G. Gomes Liszt Y. C. Madruga Ketul C. Popat Hermes de Souza Costa Roberta M. Sabino

Bacterial infections and the lack of bioactivity of titanium implants and their alloys remain critical challenges for the long-term performance and clinical success of these devices. These issues arise from the undesirable combination of early microbial adhesion and the limited ability of metallic surfaces to form a bioactive interface capable of supporting osseointegration. To address these limitations simultaneously, this study employed electrical discharge machining (EDM), which enables surface topography modification and in situ incorporation of bioactive ions from the dielectric fluid. Ti-6Al-4V ELI surfaces were modified using two dielectric fluids, a fluorine/phosphorus-based solution (DF1-F) and a calcium/phosphorus-based solution (DF2-Ca), under positive and negative polarities. The recast layer was characterized by SEM and EDS, while bioactivity was evaluated through immersion in simulated body fluid (SBF) for up to 21 days. Antibacterial performance was assessed against Staphylococcus aureus at 6 h and 24 h of incubation. The results demonstrated that dielectric composition and polarity strongly influenced ionic incorporation and the structural stability of the modified layers. The DF2-Ca(+) condition exhibited the most favorable bioactive response, with Ca/P ratios closer to hydroxyapatite and surface morphologies typical of mineralized coatings. In antibacterial assays, Ca/P-containing surfaces significantly decreased S. aureus attachment (>80–90%). Overall, EDM with Ca/P-containing dielectrics enables the fabrication of Ti-6Al-4V surfaces with enhanced mineralization capacity and anti-adhesive effects against Gram-positive bacteria, reinforcing their potential for multifunctional biomedical applications.

Colloids and Interfaces doi: 10.3390/colloids10010011

Authors: Chenhui Song Junmou Zhou Zhuoheng Wu Lehao Liu Jinkui Zhang Junfeng Ma

Bismuth vanadate (BiVO4) has been regarded as a valuable semiconductor material for photocatalytic decomposition of organic pollutants thanks to its narrow band gap and environmental friendliness. However, its practical application is restricted by its small specific surface area, severe photo-generated carrier recombination, and low photocatalytic degradation efficiency. Herein, a microemulsion method followed by a hydrothermal process is developed to prepare a flower-like BiVO4 microsphere constituted of thin nanosheets. Because of increase in reactive sites, facilitation of photo-induced carrier transfer, and generation of high-activity superoxygen (•O2−) and hydroxyl (•OH) radicals, the photocatalytic degradation efficiency of the flower-like BiVO4 microparticle (synthesized with a hydrothermal duration of 6 h) for Congo red reaches 86.2% with a high degradation rate constant of 0.0134 min−1. Moreover, the cyclic degradation test proves the reasonable photocatalytic stability of the flower-like BiVO4 microparticle, showing its great application potential for photocatalytic degradation of organic pollutants.

Colloids and Interfaces doi: 10.3390/colloids10010010

Authors: Nojod H. Hasaballah Shareefa Abdullah AlGhamdi Adeel G. Chaudhary Hanan Aati Jawzaa Almutairi Shahd Moqaddam Gumana Alkathiri Ola Alahmadi Abdullah Salwati Rinad Abuzinadah Khalil Alkuwaity Wala Andejani Hossam H. Tayeb

Antimicrobial resistance is driving the urgent need for novel antimicrobials. Nanoemulsions (NEs) offer alternatives to traditional antimicrobials by improving the physiochemical and biological properties of bioactive compounds. Artemisia absinthium essential oil (Art-EO) has antimicrobial and antioxidant properties, although its medical applications are limited by hydrophobicity and potential cytotoxicity. To improve these properties, this study investigated an NE loaded with Art-EO (Art-EO NE) extracted via hydrodistillation from A. absinthium grown in Saudi Arabia. Extracted with 0.92% (v/w) yield from the aerial parts of A. absinthium, Art-EO was analysed by gas chromatography–mass spectrometry, revealing 29 compounds. The Art-EO NE, prepared using ultrasonication, showed a droplet size of 116 ± 0.2 nm, polydispersity index of 0.14 ± 0.0, and zeta potential of −23.9 ± 1.0 mV determined by dynamic and electrophoretic light scattering. The NE remained physically stable for two months and exhibited antimicrobial activity for one week. Compared to the Art-EO aqueous extract (minimum inhibitory concentration (MIC): 20% v/v Art-EO), the Art-EO NE enhanced antibacterial activity against Staphylococcus aureus by 32-fold (MIC: 0.625% v/v Art-EO). The NE also exhibited potent antioxidant activity and produced an acceptable in vivo safety profile. These findings present Art-EO NEs as effective antimicrobial and antioxidant agents.

Colloids and Interfaces doi: 10.3390/colloids10010009

Authors: Petr Filip Martin Pivokonsky

The van der Waals (vdW) interaction energy is a crucial factor in evaluating the potential destabilization of colloidal systems, such as those found in drinking-water treatment, where particles are often assumed to be spherical. Although the explicit dependence of the vdW interaction energy on the radii of spherical particles and their distances is known, a simple view is lacking due to the complexity of the relations. Here, we propose explicit, algebraically simple, approximate relations that provide insight into the fundamental influence of the input geometrical parameters. These relations, when combined with the exponentially decaying potential generated by the electrical double layer, can provide an approximate evaluation of the onset of raw water destabilization in drinking-water treatment, in other words, establishing the conditions under which pollutants in raw water begin to aggregate.

Colloids and Interfaces doi: 10.3390/colloids10010008

Authors: Sujit Kumar Shah Rojina Bhattarai Sujata Gautam Pawan Shah Ajaya Bhattarai

In this study, cationic surfactant cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) are employed to systematically investigate surface and wetting properties on hydrophobic surfaces, specifically in mixed solvents composed of ethylene glycol (EG) and water at 298.15 K. By varying the concentration of each surfactant within the EG–water mixture, both surface tension and contact angle measurements are performed to elucidate how surfactant type and solvent composition influence interfacial behavior and wettability. PTFE and wax surfaces were chosen as model hydrophobic surfaces. Surface tension measurements obtained in pure water and in water–EG mixtures containing 5, 10, and 20 volume percentage EG reveal a consistent decrease in the premicellar slope (dγdlogC) with increasing EG content. This reduction reflects weakened hydrophobic interactions and less effective surfactant adsorption at the air–solution interface. The corresponding decline in maximum surface excess (Γmax) and increase in minimum area per molecule (Amin) confirm looser interfacial packing due to EG participation in the solvation layer. Plots of adhesion tension (AT) versus surface tension (γ) exhibit negative slopes, consistent with reduced solid–liquid interfacial tension (ΓLG) and greater redistribution of surfactant molecules toward the solid–liquid interface. AOT shows stronger sensitivity to EG compared to CTAB, reflecting structural headgroup-specific adsorption behavior. Work of adhesion (WA) measurements demonstrate enhanced wettability at higher EG concentrations, highlighting the cooperative impact of co-solvent environment and surfactant type on wetting phenomena.

Colloids and Interfaces doi: 10.3390/colloids10010007

Authors: Kamyar Shameli Behnam Kalali Hassan Moeini Aras Kartouzian

Lipid nanoparticles (LNPs) are now the go-to method for delivering genetic medicines, backed by real-world use in patients. Things like which fats they are made of, their shape at the molecular level, how ingredients mix, and how they are built, matter a lot. This review attempts to take a close look at how different components, such as ionizable lipids, auxiliary lipids (DSPC, DOPE), cholesterol, and PEG-based lipids, affect the bioavailability of LNPs. It also focuses on key functions of LNPs, including packaging genetic material, escaping cellular traps, spreading in the body, and remaining active in the blood. New data show that lipids with the right handedness and highly sensitive chiroptical quality control can sharpen delivery accuracy and boost transport rates, turning stereochemistry into a practical design knob. Rather than simply listing results, we examine real-world examples that are already used to regulate gene expression, enhance mRNA expression, splenic targeting, and show great potential for gene repair, protein replacement, and DNA base-editing applications. Also, recent advances in AI-based designs for LNPs that take molecular shape into account and help speed up modifications to lipid arrangements and mixture configurations are highlighted. In summary, this paper presents a practical and scientific blueprint to support smarter production of advanced LNPs used in genetic medicine, addressing existing obstacles, balanced with future opportunities.

Colloids and Interfaces doi: 10.3390/colloids10010006

Authors: Orathai Loruthai Sornkanok Vimolmangkang Wannita Klinngam

Nanoemulsions (NEs) offer a promising strategy for delivering lipophilic cannabidiol (CBD) to protect skin from particulate matter (PM)-induced damage. In this study, CBD-loaded oil-in-water NEs based on Brij® O10 (polyoxyethylene (10) oleyl ether) and olive oil were prepared by the phase inversion temperature (PIT) method and characterized. A 20% w/w Brij® O10 formulation (B20) remained clear and stable for 30 days. CBD solubility was markedly enhanced in Brij® O10 micelles and further increased in NEs, exceeding theoretical predictions and indicating synergistic solubilization in the oil–surfactant system. CBD incorporation lowered the PIT and induced nonlinear changes in droplet size with oil content. All formulations exhibited nanoscale droplets by dynamic light scattering and transmission electron microscopy, moderately low zeta potentials consistent with nonionic steric stabilization, and maintained physical stability despite increased turbidity at higher oil levels. In a full-thickness human ex vivo skin model exposed to PM, both blank and CBD-loaded NEs reduced interleukin-6 (IL-6) and matrix metalloproteinase-1 (MMP-1) in PM-exposed skin, with CBD-loaded NEs providing additional reductions and uniquely restoring procollagen type I C-peptide (PIP) relative to their blanks. Overall, PIT-based CBD NEs enhance CBD solubilization and protect human ex vivo skin from PM-induced inflammation and extracellular matrix degradation.

Colloids and Interfaces doi: 10.3390/colloids10010005

Authors: Sourav Gurung Monalisha Sarmin Muddasarul Hoda

Background: The aqueous and methanolic extracts (AE and ME) of Bergenia ciliata leaves have contradictory silver nanoparticles (AgNP) synthesis potential, influenced by photoirradiation. Method: In the current study, photoirradiation-mediated AgNP synthesis potential of two sub-extracts of ME, namely aqueous precipitated ME (PME) and aqueous dissolved ME (DME), were studied through comparison of their physicochemical properties. Results: In dark, DME demonstrated significant AgNP synthesis, whereas PME did not synthesize AgNPs. However, photoirradiation reversed the role of both the sub-extracts in nanoparticles synthesis. PME also demonstrated an inhibitory effect on AE-mediated AgNP synthesis in dark. GC-MS identified pyrogallol as the major reducing agent in both the sub-extracts. Photoirradiation significantly influenced the nanoparticle size and percent elemental composition of the AgNP. In dark, PME and DME produced AgNP of approx. 23.94 nm and 31.08 nm diameters, respectively, which significantly increased to 47.26 nm and 47.48 nm, respectively, on photoirradiation. Although no significant change in the percent silver composition was observed in PME-AgNP on photoirradiation (approx. 68%), DME demonstrated enhanced silver percent from approx. 58% to 72% on photoirradiation. Both DME- and PME-AgNPs were stable up to 15 days at 4 °C. Conclusions: PME has photoirradiation-mediated dual property of inhibition and enhancement of AgNPs synthesis.

Colloids and Interfaces doi: 10.3390/colloids10010004

Authors: Venkatakrishnan Kiran Anbazhagan Thirumalai Pazhani Durgadevi Najim Akhtar Alex Daniel Prabhu Koyeli Girigoswami Agnishwar Girigoswami

Magnetoliposomes are hybrid nanostructures that integrate superparamagnetic ultrasmall carbon-coated ferrite nanodots (MNCDs) within liposomes (Lipo) composed of egg yolk-derived phospholipids and stabilized with an environmentally benign potato peel extract (PPE), enabling enhanced magnetic resonance imaging (MRI) and optical imaging. The hydrothermally synthesized MNCDs were entrapped in liposomes prepared by thin-film hydration, and physicochemical properties were established at each stage of engineering. These magnetoresponsive vesicles (MNCDs+Lipo@PPE) serve as a triple-mode medical imaging contrast for T1 & T2-weighted MRI, while simultaneously enabling optical tracking of liposome degradation under an external magnetic field. They exhibited long-term enhanced fluorescence intensity and colloidal stability over 30 days, with hydrodynamic diameters ranging from 190 to 331 nm and an improved surface charge following PPE coating. In vitro cytotoxicity assays (MTT and Live/Dead staining) demonstrated over 87% cell viability for MNCDs+Lipo@PPE up to 2.7 mM concentration in A549 cells, indicating considerable toxicity. This multimodality engineering facilitates precise image-guided anticancer doxorubicin delivery and magnetic-responsive controlled release. The theoretical model shows that the release profile follows the Korsmeyer-Peppas profile. The externally applied magnetic field enhances the release by 1.4-fold. To demonstrate the anticancer efficiency in vitro with minimum off-target cytotoxicity, MTT and live/dead cell assay were performed against A549 cells. The reported study is a validated demonstration of magnetic-responsive nanocarrier systems for anticancer therapy and multimodal MRI and optical imaging-based diagnosis.

Colloids and Interfaces doi: 10.3390/colloids10010003

Authors: Saule B. Aidarova

Volume 8 of the book series ‘Progress in Colloid and Interface Science’ is dedicated to emulsions and their building blocks, the adsorption layers at the surface of emulsion drops and the liquid films between the drops [...]

Colloids and Interfaces doi: 10.3390/colloids10010002

Authors: Elham Ommat Mohammadi Samira Yeganehzad Regine von Klitzing Reinhard Miller Emanuel Schneck

This study aimed to elucidate the impact of Persian Gum (PG; Amygdalus scoparia Spach) on the heat-induced aggregation and interfacial behavior of whey protein isolate (WPI). To achieve this, pure WPI and mixed WPI-PG systems were subjected to thermal treatments between 25 and 85 °C, and their structural and functional changes were characterized using fluorescence spectroscopy, UV-vis absorption, turbidity and bulk viscosity measurements, interfacial shear and dilatational rheology, and foaming assessments. The presence of PG altered the aggregation pathway of WPI in a temperature-dependent manner, producing smaller, more soluble complexes with lower turbidity, particularly at higher temperatures. Both pure WPI and WPI-PG mixtures exhibited increased surface hydrophobicity upon heating; however, PG generally reduced the dilatational elastic modulus except at 85 °C, where the mixed system showed a higher modulus than WPI alone. In contrast, the interfacial shear modulus increased over time in all samples, with consistently higher values observed for WPI-PG mixtures at both 25 °C and 85 °C. Notably, three complementary methods were employed to evaluate foaming properties and interfacial behavior in this study, revealing that factors such as concentration, measurement time, and methodological approach strongly influence the observed responses, highlighting the complexity of interpreting protein-polysaccharide interactions. The ability of PG to modulate WPI unfolding and limit the formation of large aggregates during heating demonstrates a previously unreported mechanism by which PG tailors heat-induced protein network formation. These findings underscore the potential of Persian Gum as a functional polysaccharide for designing heat-treated food systems with controlled aggregation behavior and optimized interfacial performance.

Colloids and Interfaces doi: 10.3390/colloids10010001

Authors: Rasmus Kranold Mikkelsen Ioanna Fragkaki Simon Gregersen Echers Naim Abdul-Khalek Michael Toft Overgaard Charlotte Jacobsen Betül Yesiltas

Brewers’ spent grain (BSG) represents the major byproduct of the brewing industry and remains largely underutilized. While BSG contains a rather high amount of protein, poor functional properties limit its use as a functional ingredient for foods without additional processing. In this work, we investigate emulsifying peptides embedded in the major BSG proteins based on a mass spectrometry-based proteomic analysis and subsequent bioinformatic prediction to explore the utilization of BSG as a raw material for the production of protein-based emulsifying ingredients. Forty-eight peptides were selected based on EmulsiPred score, amino acid sequence, and protein abundance for evaluation. All peptides effectively reduced the interfacial tension between oil–water, but only 15 could produce and stabilize emulsions with droplet sizes below 5 µm. Some peptides were able to produce stable emulsions with sub-micron droplet sizes, implying very promising emulsifying properties. This study demonstrated promising emulsifying properties of BSG peptides and suggested that the functionality could be predicted using bioinformatic tools. However, the used tool needs to be further optimized for higher success rate.

Colloids and Interfaces doi: 10.3390/colloids9060089

Authors: Boris A. Noskov Alexey G. Bykov Alexandra D. Khrebina Evlaliya A. Levchuk Giuseppe Loglio Reinhard Miller Egor A. Tsyganov

The formation of mixed adsorption layers of amyloid fibrils of a plant protein, oat globulin (OG), and a strong polyelectrolyte, sodium polystyrene sulfonate (PSS), at the liquid–gas interface was studied by measurements of the kinetic dependencies of surface tension, dynamic surface elasticity, and ellipsometric angle. The micromorphology of the layers was determined by atomic force microscopy. A strong increase in the surface elasticity was discovered when both components had similar concentrations and formed a network of threadlike aggregates at the interface, thereby explaining the high foam stability in this concentration range. The sequential adsorption of PSS and OG resulted in the formation of thick mixed multilayers and the surface elasticity increased with the number of duplex layers.

Colloids and Interfaces doi: 10.3390/colloids9060088

Authors: Aleksandr Degterev Aleksandr Tarasov Mariya Degtereva Marina Pavlova Nikita Khorshev Yevgeniy Levin Ivan Mikhailov Dmitriy Testov Ivan Lamkin Sergey Tarasov

Triple-cation perovskite solar cells, such as Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3 (hereinafter referred to as CsFAMA) have high efficiency (>26%), but their stability is limited by phase segregation and defects at grain boundaries. In this work, the effect of formic acid (HCOOH) on suppressing the degradation of perovskite films is investigated. It is shown that the addition of HCOOH to the precursor solution reduces the size of colloidal particles by 90%, which contributes to the formation of highly homogeneous films with a photoluminescence intensity deviation of ≤3%. Structural analysis and dynamic light scattering measurements confirmed that HCOOH suppresses iodide oxidation and cation deprotonation, reducing the defect density. Aging tests (ISOS-D) demonstrated an increase in the T80 lifetime (time to 80% efficiency decline) from 158 to 320 days for the modified cells under ambient conditions at room temperature and 40% relative humidity. The obtained results indicate a key role of HCOOH in stabilizing CsFAMA perovskite by controlling colloidal dynamics and defect passivation, which opens up prospects for the creation of commercially viable PSCs.

Colloids and Interfaces doi: 10.3390/colloids9060087

Authors: Martina Cofelice Antonella De Leonardis Francesco Letizia Massimo Iorizzo Francesca Cuomo Francesco Lopez

The food industry is actively seeking solutions to reduce or replace conventional petroleum-based plastic packaging and, at the same time, to identify strategies that limit the rapid deterioration of fresh products. In this context, the present study evaluated the effectiveness of an edible emulsion coating based on lemongrass essential oil and alginate in delaying the spoilage of Lactuca sativa salad. Following rheological investigation, 1% alginate emulsion was selected as the coating formulation and applied by spraying onto fresh-cut lettuce, and the effect of the treatment was monitored throughout storage. Fresh-cut Lactuca sativa salad was assessed in terms of weight loss, pH, titratable acidity, visual appearance, sensory analysis, and microbiological contamination. Measurements of weight loss, pH, and titratable acidity indicated the lack of significant differences between coated and uncoated salads leaves. However, coated samples exhibited improved quality in the first 8 days of storage, particularly with evidence of a reduction in psychrotrophic and mesophilic bacteria. The proposed coating also helped to preserve the visual appearance of the leaves, with no visible browning during storage, and the sensory evaluation results were encouraging. Overall, these findings suggest that the technology investigated is promising for supporting the use of emulsion-based edible coatings to reduce the rapid spoilage of Lactuca sativa salad during storage.

Colloids and Interfaces doi: 10.3390/colloids9060086

Authors: Andrey Minakov Vladimir Zhigarev Angelica Skorobogatova Dmitriy Guzei Andrey Pryazhnikov Maxim Pryazhnikov Sergey Lubenets Roman Vaganov

This article presents the results of experimental studies examining the effectiveness of low-concentration nanoemulsions for enhanced oil recovery (EOR). The maximum volume concentration of diesel fuel in the emulsions did not exceed 1% by volume. The volume concentration of the emulsifier ranged from 0.05% to 0.4%. A method for preparing stable nanoemulsions was developed. The colloidal stability, viscosity, interfacial tension, wettability, and capillary imbibition rate of low-concentration nanoemulsions were studied. Filtration experiments were conducted to study oil displacement on microfluidic chips simulating a porous medium and core samples. This is the first systematic study of the properties of nanoemulsions containing diesel fuel. It was demonstrated that the developed emulsions have high potential for EOR. It was shown that increasing the emulsifier concentration reduces the contact angle from 35 to 16 degrees and halves the surface tension coefficient. Experiments studying the capillary imbibition of oil-saturated cores with nanoemulsions also confirmed their ability to reduce interfacial tension and improve rock wettability. Oil displacement efficiency during capillary imbibition increases by 22%. Filter tests on microfluidic chips and core samples confirmed the high efficiency of the developed nanoemulsions. Increasing the emulsifier concentration in the emulsion to 0.4% increases the displacement efficiency from 32% for water displacement to 57% for nanoemulsion displacement. Core tests showed that additional injection of nanoemulsions significantly increases the oil displacement efficiency by 10–14%, depending on the emulsifier concentration in the nanoemulsion. It was also established that the use of an aqueous solution of an emulsifier without a hydrocarbon phase does not provide such a significant increase in the displacement coefficient as in the emulsion composition.

Colloids and Interfaces doi: 10.3390/colloids9060085

Authors: Jun Wang Hao Lin Qizhong Chan Yaohong Zhao Xiaohui He

Liquid organic hydrogen carriers (LOHCs) are promising materials for safe, reversible, and high-density hydrogen storage. Atomically dispersed bimetallic Pt–Sn nanocluster catalysts supported on TiO2 (Pt–Sn/TiO2) were developed to enhance the hydrogenation step in the toluene-methylcyclohexane cycle, a model LOHC system. Compared with monometallic Pt/TiO2 and Sn/TiO2, Pt–Sn/TiO2 exhibited superior hydrogenation performance. Mechanistic studies, including X-ray photoelectron spectroscopy, kinetic analysis, and H2-D2 exchange experiments, revealed that Sn incorporation modulates the electronic structure of Pt, enhancing H2 activation and spillover. These findings provide insights into the rational design of atomically dispersed bimetallic nanocluster catalysts for efficient and durable hydrogen storage in LOHC-based systems.

Colloids and Interfaces doi: 10.3390/colloids9060084

Authors: Monica Tonelli Massimo Bonini

Reversible adhesives enable temporary yet robust bonding between surfaces, allowing controlled detachment without structural or interfacial damage. This capability is gaining increasing recognition as a crucial requirement for sustainable technologies, where repairability, reusability, and minimal waste are key objectives. Among the diverse strategies explored for reversible adhesion (including supramolecular assemblies, bioinspired dry adhesives, and stimuli-responsive polymers), hydrogel-based systems have emerged as particularly versatile candidates due to their tunable mechanics, elasticity, and intrinsic biocompatibility. Recent studies highlight the use of renewable or biodegradable polymers to develop sustainable, water-rich hydrogel networks with controllable adhesive properties, minimizing environmental impact while maintaining performance. Despite these advances, significant challenges still hinder full implementation: biopolymer-based systems such as chitosan or starch often exhibit strong but poorly controllable adhesion, compromising reversibility and reusability. This review provides a comprehensive overview of strategies for developing hydrogel-based reversible adhesives, focusing on sustainable material selection, molecular design principles, and the underlying mechanisms of bonding and debonding. Furthermore, characterization methodologies, from conventional mechanical testing to surface-sensitive and dynamic techniques, are discussed in detail to establish structure–property–function relationships. Finally, emerging directions and application opportunities are outlined, offering a framework for the rational design of next-generation, sustainable adhesive systems.

Colloids and Interfaces doi: 10.3390/colloids9060083

Authors: Anna Y. Gyurova Ljubomir Nikolov Elena Mileva

A detailed investigation of the structure–property relationships of three-antennary oligoglycines in aqueous solutions is performed. Two representatives of these substances are investigated: CH3C(-CH2-NH-Gly5)3 and CH3C(-CH2-NH-Gly7)3. The aim is to clarify the effect of molecular peculiarities and the concentration of the oligoglycines on bulk-solution performance and on adsorption-layer properties at the solution–air interface. This study is focused on the clarification of the conditions for the onset of bulk and interfacial supramolecular species in the aqueous environment. The presence of oligoglycine antennae attached to a common carbon-atom center allows the formation of highly coordinated intra- and intermolecular ‘click-clack’ interactions and presumes the possibility for the development of extended H-bonded networks, e.g., in the form of Polyglycine II motifs. A combined study protocol, including dynamic light scattering, profile analysis tensiometry, and microscopic thin-liquid-film techniques, is applied. The results allow the drawing of essential conclusions about the possible coupling mechanism of bulk and interfacial phenomena. The outcomes give grounds to advance the following hypothesis: due to the synchronized action of noncovalent interactions, three types of tectomeric structures may appear—dimers, gel-like elements, and disk-like supramolecular entities. Options for fine-tuning of the tectomer formation in aqueous solutions are presented, and possible application routes are outlined.

Colloids and Interfaces doi: 10.3390/colloids9060082

Authors: Tianyu Cao Fu Han

This study systematically compares how three counterions (Na+, K+, NH4+) regulate the interfacial properties, foaming behavior, and foam stability of lauroyl glutamate (LG) surfactants, and further examines how added NaCl modifies these properties in the sodium salt (SLG). The three counterions induce only slight variations in surface activity and foam generation. Their influence is more evident in foam stability, with the sodium salt exhibiting enhanced stability across a wider concentration range. For SLG, NaCl addition markedly lowers the critical micelle concentration and induces concentration-dependent changes in foaming behavior: 1% NaCl enhances foam generation, while higher salt levels diminish this effect. Foam stability is strongly affected in the sub-cmc regime, with 3% NaCl producing the most stable foams. Surfactant concentration and salt content are the main factors affecting foam performance.

Colloids and Interfaces doi: 10.3390/colloids9060081

Authors: Wenghong Fong Yalini Sadasivam Awatif Belkhiri-Baines Valerie Pinfield Anna Trybala

This study investigates the apparent surface-active and emulsifying behaviour of raw Albizia amara (AA) powder suspended in water, reflecting its traditional mode of use. AA suspensions (0.1–1% w/v) were prepared without extraction and evaluated for apparent surface tension, droplet size distribution, emulsification capacity, and emulsion stability. Increasing AA concentration reduced apparent surface tension from 57.13 ± 2.17 mN/m to 48.9 ± 0.06 mN/m, plateauing at higher concentrations. Both blending and high-shear mixing produced oil-in-water emulsions. Blending generated smaller initial droplets (1–10 µm), whilst high-shear mixing produced more uniform distributions (d50 = 31.23 ± 0.95 µm). Emulsion capacity and stability increased with AA concentration, reaching 95.19 ± 3.39% and 89.81 ± 0.02% at 0.8% AA. As the system contains undissolved plant material, all measurements represent the apparent behaviour of a heterogeneous suspension. The specific molecular contributors to surface activity cannot be identified within this study. These findings provide a baseline physicochemical assessment of raw AA powder and support future work involving extraction, purification, and chemical characterisation to establish the mechanisms underlying its surface-active properties.

Colloids and Interfaces doi: 10.3390/colloids9060080

Authors: Harsh B. Jadhav Dheeraj Kumar Federico Casanova

The functional characteristics of Partial acylglycerols (PAGs) have attracted the attention of researchers in designing PAGs for food applications as a potential substitute for conventional fats/oils. Designing PA using enzymes has been of great interest due to the greater specificity of enzymes, giving high-quality products for food applications. The utilization of PA in fat-based products, such as bakery, dairy, and emulsion foods, exhibits superior functionalities and health-friendly characteristics. The PA can also be used for cooking/frying applications. However, exposure of PA to a higher temperature for a longer time shows inferior characteristics. The functional characteristics of PA, such as solid fat content, rheology, microstructure, crystal formation, and thermal behavior, make it a potential replacement for conventional fat. The present review focuses on a comparative assessment of synthetic routes, the functional characteristics of PA, food applications, and technological drawbacks in commercializing PA-based products. Furthermore, the future prospect focuses on supporting future research that will facilitate the incorporation of PA in food products at an industrial scale.

Colloids and Interfaces doi: 10.3390/colloids9060079

Authors: Bojana Katana Duško Čakara

Proton binding (i.e., charging) isotherms of halloysite nanotubes (HNT) were determined from cycled acid-base potentiometric titrations in KCl solution at constant ionic strengths (0.01, 0.10, 1.00 mol dm−3). The isotherms measured in the pH cycle from 3 to 11 and back exhibit a pronounced hysteresis with respect to the direction of pH change, which is accurately reproducible when the cycle is repeated. The hysteresis is absent if the cycled titration is performed within a narrow pH range between 5 and 9. These results align with the dissolution rates of alumina and silica, which form the two surfaces of the rolled kaolinite sheet in HNT, and clearly point to reversible partial dissolution-deposition processes in the HNT interior during a titration cycle, outside the above pH range (alumina dissolution below pH ≈ 5 and silica dissolution above pH ≈ 8.5). In the studied titration experiments, these processes produce partially dissolved surface-bound, rather than completely dissolved species (reversible surface etching). Under the applied conditions, reversible surface etching is less pronounced in the acidic part of the titration cycle. Charging isotherms recorded in the decreasing pH titrations at varied ionic strength exhibit a common intersection point very close to zero charge (point of zero charge) around pH ≈ 8.1, characteristic for an amphoteric solid surface. These isotherms were reasonably well fitted by applying the surface protonation model in the HNT interior, which invokes the Stern model of the electric double layer (EDL), by summing the surface charges calculated for alumina and silica as separate components (surfaces). The model surface charge isotherms for alumina surface in the HNT interior exhibit a point of zero charge at pH = 9.0, while the silica surface has a negative charge above pH > 8.5, which is in very good agreement with the values reported in the literature: as for these two surfaces, thus for kaolinite nanoparticles. The best-fit protonation site density for both surfaces is equal to 8.0 nm−2, while the best-fit intrinsic pKa for alumina and silica surfaces of HNT are equal to 9.0 and 8.5, respectively. The pH-dependence of electrophoretic mobility, measured by means of electrophoretic light scattering, reveals a more acidic behavior of the outermost silica surface than within the inner HNT phase, which is consistent with the literature result reported for kaolinite. The results reported herein confirm that the inner and outer surfaces of the HNT are oppositely charged below pH < 8.0 and negatively charged above that value, and importantly, they reveal new details about the protonation affinities and EDL parameters at active surfaces of HNT, important for the colloidal stability of HNT suspensions and the functionalization of HNT through the electrostatic binding of active molecules.

Colloids and Interfaces doi: 10.3390/colloids9060078

Authors: James R. Zelaya Gary C. Tepper

The aim of this study was to investigate the nucleation, growth, and surface deposition of poly(2,2,2-trifluoroethyl methacrylate) [poly(TFEMA)] from the one-phase, cloud point, and two-phase regions of a supercritical CO2–toluene solvent. A ternary mixture of 20 wt% toluene + 79 wt% scCO2 + 1 wt% poly(TFEMA) at 40.0 °C was exposed to a fluorine-doped tin oxide (FTO) surface for 30 min at pressures placing the solution in (i) a one-phase region (15.86 MPa), (ii) the cloud point (12.37 MPa), and (iii) a two-phase region (8.96 MPa). Using the Altunin–Gadetskii–Haar–Gallagher–Kell (AG–HGK) equation of state (EOS), the corresponding CO2 densities are 793.9, 729.2, and 477.8 kg m−3. Scanning electron microscopy (SEM) and particle-size analysis (sample sizes N = 852–1177) show particle-size distributions (PSDs) that are well described by the following lognormal form: the mean diameter increases monotonically with a decrease in pressure (1.767 μm → 2.605 μm → 2.863 μm), while dispersion tightens slightly near the cloud point (coefficient of variation, CV: ≈0.47 → 0.44) and then broadens strongly in the two-phase region (CV ≈ 1.02). Morphologies transition from sparse, compact islands (one-phase) to agglomerated, necked spheres (cloud point) and finally hierarchical populations containing hollow/pitted large particles (two-phase). These outcomes are consistent with a phase-state-controlled shift in nucleation pathways, as follows: from heterogeneous surface nucleation in the one-phase regime to homogeneous nucleation with agglomeration at the cloud point, and to homogeneous nucleation with coalescence and solvent capture in the two-phase regime. The results provide a mechanistic basis and practical design rules for pressure-programmable control of fluoropolymer coatings prepared from scCO2/aromatic-cosolvent systems.

Colloids and Interfaces doi: 10.3390/colloids9060077

Authors: Eleni P. Kalogianni Julia Maldonado-Valderrama

This Special Issue features a collection of research papers following the 19th Food Colloids Conference, organized by the International Hellenic University and held on the 14–18 April 2024 in Thessaloniki, Greece [...]

Colloids and Interfaces doi: 10.3390/colloids9060076

Authors: Qingqing Xing Fei Li Pingtian Ming Zhen Wang

This study investigated the flotation performance of W8, a blended xanthate collector containing ethyl, butyl, propyl, and amyl xanthates, combined with ammonium dibutyl dithiophosphate (ADD) for treating low-grade arsenopyrite-type gold ore from Golmud, Qinghai. Real ore flotation tests demonstrated the superior efficacy of the W8 + ADD system, achieving 84.06% gold recovery with 0.34 g/t tailings, outperforming conventional sodium amyl xanthate (SAX) + ADD and sodium propyl xanthate (SPX) + ADD systems. Systematic studies on pure arsenopyrite revealed a significant synergistic effect in the mixed SPX-SAX system (1:4 ratio), representative of W8 composition. At pH 9, the mixed collector achieved 73.5% recovery, substantially higher than individual SPX (37.5%) or SAX (45.8%). This enhanced performance was attributed to improved surface hydrophobicity (contact angle 47.68° vs. 36.92° for SAX), greater adsorption density (4.97 × 10−7 mol/g under depressant conditions), and extensive formation of molecular aggregates observed via AFM, which increased surface roughness to 28.95 nm. Flotation kinetics further confirmed the advantage of W8 + ADD, which reached 72.1% cumulative recovery in 420 s, exceeding both mixed SPX/SAX (69.5%) and single SAX (65.5%) systems. The synergistic interaction among different xanthate components in W8 enables efficient recovery of gold from this refractory ore.

Colloids and Interfaces doi: 10.3390/colloids9060075

Authors: Abhijit Dan

The book series Progress in Colloid and Interface Science was launched in 2009 by Libero Liggieri and Reinhard Miller [...]

Colloids and Interfaces doi: 10.3390/colloids9060074

Authors: Xinjun Yao Wanrong Li Jun Guo Fangkai Han Muhammad Usman Lipeng Wu

Carboxymethyl chitosan (CMCS) is ideal for active packaging due to its non-toxicity and degradability, but its poor film-forming performance (strong hydrophilicity, weak mechanical properties, and low antibacterial activity) limits practical use. This study prepared a new edible antibacterial presFervation film (SDEWL-CMCS) by adding salted duck egg white lysozyme (SDEWL) to CMCS (as the film-forming substrate). It investigated how SDEWL concentration affects the composite film’s properties (thickness, water solubility, moisture/oil resistance, mechanical properties, and antibacterial activity) and tested the film’s preservation effect on small nectarines. The results showed the composite film had significantly improved packaging and antibacterial properties: compared to pure CMCS film, it had higher tensile strength, lower water solubility, better oil resistance and water vapor barrier performance, and stronger antibacterial activity against Escherichia coli and Staphylococcus aureus (larger inhibition zone diameters). The SDEWL-CMCS film effectively preserved small nectarines by inhibiting surface bacteria, regulating the preservation environment, and delaying fungal decay. This study confirms the film’s potential as a sustainable fruit packaging alternative, providing a theoretical basis for developing new fruit/vegetable preservation packaging and reducing the food industry’s reliance on non-degradable petroleum-based packaging.

Colloids and Interfaces doi: 10.3390/colloids9060073

Authors: Reinhard Miller

The journal Colloids and Interfaces is a platform dedicated to all aspects of colloids and interfaces chemistry [...]

Colloids and Interfaces doi: 10.3390/colloids9050072

Authors: Hazel Cox Mark L. Brusseau

Manufactured nanoparticles are used in many consumer products and industries, and are known to enter our waste streams. Transport of nanoparticles in porous media has been studied extensively; however, the forces governing the interactions between nanoparticles and naturally porous media surfaces are still not fully understood. To examine the retention mechanisms and forces involved in nanoparticle transport, miscible–miscible transport experiments were performed and followed by force profile measurements by Atomic Force Microscopy (AFM). TiO2 nanoparticles were used as the model nanoparticle, with silica sand as the model natural porous medium. Solution chemistries were varied from pH 4.5 (favorable attachment) to 8 (unfavorable attachment), and at 0.0015–30 mM ionic strength. Detachment transport experiments were performed for the unfavorable attachment conditions to determine if secondary minima attachment was present. DLVO calculations were performed to evaluate their predictive ability for force profiles under the experimental conditions. Mass recoveries for the transport experiments ranged from 28% to 80%, indicating significant attachment. Detachment was observed, indicating the presence of secondary minima. The magnitudes of attachment measured for the transport experiments were generally consistent with the results of the AFM measurements. In addition, the detachment observed at the highest pH was also consistent with the predictions, indicating the presence of secondary minima. DLVO theory underestimated the magnitudes of the attractive and repulsive forces measured by AFM but was able to qualitatively represent behavior observed at the lower two pHs. In contrast, it provided a poor representation of behavior at the highest pH. The integrated AFM measurements and miscible–displacement experiments employed in this study have provided insight into the retention of TiO2, with implications for other nanoparticles during transport in porous media.

Colloids and Interfaces doi: 10.3390/colloids9050071

Authors: Zhenlong Song Yibo Hu Yanguang Shan

The drying of nanofluid films on a surface can form various patterns and plays an important role in painting, surface patterning, and nano-fabrication processes. In this paper, a two-dimensional Kinetic Monte Carlo (KMC) model is developed based on the two-dimensional Ising model to investigate the drying patterns of nanofluids in an open domain. In the KMC model, the effective chemical potential is approximated by a linear function, in contrast to the constant value used in previous studies. This ensures that the dewetting front in the open domain consistently recedes from the edges toward the center. Simulation results show that nanoparticles, initially uniformly distributed, can assemble into branched structures that remain on the substrate after complete evaporation of the nanofluid. Furthermore, the structures observed in our study differ from the fractal cavities investigated in previous studies conducted in closed domains. A parametric study reveals that both the particle diffusion rate and the chemical potential distribution significantly influence the resulting patterns.

Colloids and Interfaces doi: 10.3390/colloids9050070

Authors: Shiyong Meng Qingsong Deng Lin Zhang Yibo Feng Lei Fan Yuxin Liu Danmin Liu Cong Wang

The practical adoption of surface-enhanced Raman scattering (SERS) technology is often hampered by the high cost, complex fabrication, and poor reproducibility of conventional substrates, which typically rely on noble metals or inefficient semiconductors. Herein, we address key challenges in the practical commercialization of surface-enhanced Raman scattering (SERS) technology by reporting a facile, scalable, and environmentally benign strategy for fabricating a hybrid SERS substrate. This approach integrates Au nanoparticles (NPs) with hydrothermally synthesized WO3 nanowires through a green photoreduction process, which is rapid, organic-solvent-free, and amenable to large-scale production. The design of the Au/WO3 nanocomposite capitalizes on the synergistic effect between electromagnetic (EM) enhancement from Au NPs and chemical mechanism (CM) enhancement via charge transfer involving the WO3 semiconductor. This synergy empowers the substrate with exceptional SERS activity, enabling the sensitive detection of Rhodamine 6G (R6G) down to 10−11 M and yielding an enhancement factor (EF) of 4.09 × 106. More importantly, this EM-CM synergy proves critical for detecting molecules with weak affinity, such as the nerve agent simulant dimethyl methylphosphonate (DMMP), achieving a significant signal enhancement of 102–103 times, which is notably challenging for conventional plasmonic substrates. Beyond sensitivity, the substrate exhibits excellent reproducibility and operational stability, which are paramount for real-world applications. This work presents a nanohybrid strategy that successfully balances scalability, stability, and sensitivity, offering a reliable and cost-effective pathway for advancing SERS technologies toward practical implementation.

Colloids and Interfaces doi: 10.3390/colloids9050069

Authors: Milton Shabeng Kgoete Conny Putsane Mokgohloa Lutendo Evelyn Macevele

Pharmaceutical contaminants such as tetracycline pose an increasing threat to aquatic ecosystems and human health as a result of their persistence in water sources and their contribution to antibiotic resistance. This study developed chitosan nanocomposites by incorporating functionalised and nitrogen-doped multi-walled carbon nanotubes (FMWCNTs and NMWCNTs) for the removal of tetracycline pharmaceutical contaminants from water. The composites were characterised with FTIR, SEM, XRD, BET, UV–Vis, and TGA under various conditions (pH, adsorbent dosage, concentration, contact time, and temperature). Optimal tetracycline removal (85%) was achieved with pH 6, 2 g/L adsorbent dose, 10 ppm concentration, and 30 min contact time. The FMWCNT–chitosan composite could be recycled five times with an adsorption loss of only 2%. The FMWCNT–chitosan composite showed the good adsorption efficiency of 82% in the presence of counter ions and 70% in a binary system. The adsorption process followed the Langmuir isotherm (263 mg/g), indicative of monolayer adsorption and pseudo-second-order kinetics. Among the nanocomposites prepared, the FMWCNT–chitosan composite showed the highest performance, removing more than 85% of tetracycline from water samples.

Colloids and Interfaces doi: 10.3390/colloids9050068

Authors: Feng Lin

Understanding adsorption and interfacial properties of surface-active agents at interfaces is crucial to the formation and stability of colloidal systems such as emulsions and foams. In this work, interfacial tension and viscoelasticity of saponin at the β-pinene/water interface were studied using drop tensiometry and dilational rheology measurement. For comparison, saponin at the air/water interface was also evaluated. Both saponin and β-pinene are bio-based, eco-friendly, and abundant in plants, trees, and agricultural wastes. Results showed that dynamic interfacial tensions σ(t) of saponin adsorbed at β-pinene/water and air/water interfaces could be well described by the Ward and Tordai model, suggesting that the saponin adsorption kinetics at both interfaces are controlled by a kinetically limited mechanism. The equilibrium interfacial pressure πe data prior to critical micelle concentration (cmc) were adequately fitted by the Gibbs adsorption isotherm. At the β-pinene/water interface, a higher cmc and a larger area per molecule, but a lower πe, were observed compared to the air/water interface. Interestingly, the dilational moduli of saponin at β-pinene/water increased with increasing oscillating frequency, but with less significant frequency dependence than their counterparts at the air/water interface. The dilational moduli of saponin at β-pinene/water passed through a minimum with increasing saponin bulk concentration, while the air/water interface exhibited a strikingly different trend in terms of concentration dependence and a higher magnitude for the dilational moduli. The correlation between adsorption behaviors and dilational properties of saponin at the two interfaces is discussed. Fundamental knowledge gained from this study will be beneficial for the rational development of new biocompatible emulsions and foam products for more sustainable applications.

Colloids and Interfaces doi: 10.3390/colloids9050067

Authors: Zhongwei Huang Na Du Wanguo Hou

The surface tensions (σ) of binary solutions of diiodomethane (DIM, 1)–furfural (FA, 2), DIM (1)–N,N-dimethylformamide (DMF, 2), and FA (1)–DMF (2) were determined at 25 °C over the entire bulk composition range, and the surface adsorption behavior was analyzed using the surface aggregation adsorption (SAA) model proposed recently. In particular, by combining the SAA model with the Gibbs adsorption equation, the changes in the Gibbs surface excess (Γ2) and the adsorption layer thickness (τ) with the bulk composition (x2,b) were investigated. The SAA model combined with the modified Eberhart model can well describe the σ-isotherms of the three binary solutions. The surface adsorption trends of component 2 in DIM–FA, DIM–DMF, and FA–DMF decrease in turn. The change trends of Γ2 and τ with x2,b are dependent on the SAA model parameters, namely, the adsorption equilibrium constant (Kx) and the average aggregation number (n). With an increase in x2,b, Γ2 continuously increases when Kx < 2v1/[n(2n − 1)v2] (where v1 and v2 are the partial molar volumes of components 1 and 2, respectively); otherwise (i.e., Kx ≥ 2v1/[n(2n − 1)v2]), Γ2 initially increases and then decreases, showing a maximum on the Γ2-isotherm. When n ≥ 1, τ gradually decreases with an increase in x2,b; otherwise (i.e., n < 1), τ initially increases and then decreases, showing a maximum on the τ-isotherm. An increase in the adsorption trend leads to a decrease in both Γ2 and τ. This work provides a better understanding of the surface adsorption behavior of liquid mixtures.

Colloids and Interfaces doi: 10.3390/colloids9050066

Authors: Zhenkun Li Tian Liu Hongchao Cui Jiahao Dong Zijian Geng Chengyao Deng Shengjie Zhang Yin Sun Heng Zhou

Yield stress and thixotropy are critical rheological properties for enabling successful 3D printing of magnetic colloidal systems. However, conventional magnetic colloids, typically composed of a single dispersed phase, exhibit insufficient rheological tunability for reliable 3D printing. In this study, we developed a novel magnetic colloidal system comprising a carrier liquid, magnetic nanoparticles, and organic modified bentonite. A direct-ink-writing 3D-printing platform was specifically designed and optimized for thixotropic materials, incorporating three distinct extruder head configurations. Through an in-depth rheological investigation and printing trials, quantitative analysis revealed that the printability of magnetic colloids is significantly affected by multiple factors, including magnetic field strength, pre-shear conditions, and printing speed. Furthermore, we successfully fabricated 3D architectures through the precise coordination of deposition paths and magnetic field modulation. This work offers initial support for the material’s future applications in soft robotics, in vivo therapeutic systems, and targeted drug delivery platforms.

Colloids and Interfaces doi: 10.3390/colloids9050065

Authors: Dimitriοs Papadimitriou Ernestos-Nikolas Sarris Andreas Georgakopoulos Nikolaos Kantiranis

This work examines the colloidal properties of clays sampled from two different locations in Ventzia basin processed as low-density solid additives for water-based drilling fluid applications. The obtained samples were mechanically processed to reach a size less than 2 cm. The material was then activated with 3 wt% soda ash without oven drying, keeping the moisture in environmental conditions to simulate industrial activation conditions. After laying for one month curing time, samples were oven dried at 60 °C and further ground to <120 μm. Two groups of samples were created mixing clays from Ventzia basin and additives. The first group contained clay, xanthan gum and sodium polyacrylate (PAA), while the second group contained clay, xanthan gum and sodium hexametaphosphate (SHMP). Standard tests were performed for the rheological behavior and filtration properties prior to and after dynamic thermal aging. Results obtained were compared with commercial clays from Milos and Wyoming used in drilling fluid systems, after thermally deteriorating also their properties. The obtained results revealed that the enhanced clays under study maintain excellent thermal stability. Notably, the top-performing formulation met the critical American Petroleum Institute (API) benchmark for filtrate loss (<15 mL) and exhibited a robust rheological profile at temperatures up to 105 °C, demonstrating its suitability for water-based fluid (WBF) applications.

Colloids and Interfaces doi: 10.3390/colloids9050064

Authors: Panos Papandreou Efstathia Triantafyllopoulou Ioannis Pispas Sophia Havaki Aristeidis Papagiannopoulos Vassilis G. Gorgoulis Natassa Pippa

Parenteral nutrition is an integral part of the nutritional support of critically ill neonates, infants, and children in the intensive care units (ICUs) and at home. Therefore, the adequacy and the effectiveness of parenteral nutrition, PN, support are among the major concerns of doctors and pharmacists. The aim of this study is the physicochemical and stability evaluation of nanoemulsions, which are used for parenteral nutrition. These nanoemulsions are for intravenous (IV) administration of lipids, amino acids, glucose, electrolytes, trace elements as well as vitamins. Light scattering techniques are used for the identification of the hydrodynamic diameter (Dh), size polydispersity index (PDI), and the ζ-potential of the prepared nanoemulsions. Stability assessment is performed in different conditions, mimicking those of the hospital. The stability studies involve shelf-life measurement of these NEs over 10 days in two storage conditions (25 °C and 4 °C) using dynamic light scattering. According to the US Pharmacopeia, the droplet size should be under the upper limit of 500 nm (0.5 μm). Transmission electron microscopy (TEM) is used for the shape of the droplets of the nanoemulsion emulsion for parenteral nutrition for the first time. The results showed that the droplet size was around 300 nm, with a homogeneous population and negative ζ-potential. The morphology was vesicular and spherical, typical for NE droplet shape. The results from all the characterization techniques show that the formulations meet the high-quality standards of nanoemulsions for neonates, infants and children.

Colloids and Interfaces doi: 10.3390/colloids9050063

Authors: Zhijian Jiang Shining Zhang Jianzhi Xu Ying Liu Yuanyuan Zhang Jianguo Liu Zicheng Zuo

Membrane innovations have become a key solution for overcoming the bottlenecks in efficiency upgrade in many green energy fields. Membrane performance depends on two key parameters permeability and selectivity, which typically follow a trade-off relationship: improving one often diminishes the other. Two-dimensional (2D) materials, which have atomic-level thickness, tunable pore sizes, and reasonable functionalization, offer great promises to break through the trade-off effect and redesign high-efficiency mass transfer pathways. This review systematically presents recent efforts in both preparation and potential applications of 2D materials for overcoming the permeability–selectivity trade-off. It highlights four prevailing fabrication strategies: chemical vapor deposition, interfacial synthesis, solution-phase synthesis, and exfoliation, and shows some major optimization techniques for various 2D materials. Additionally, this review discusses emerging applications of 2D materials across critical fields from water treatment (seawater desalination, metal ion extraction) to energy technologies (osmotic power generation, direct methanol fuel cells, and vanadium redox flow batteries). Finally, the challenges and future prospects of 2D materials in ion separation and energy conversion are discussed.

Colloids and Interfaces doi: 10.3390/colloids9050062

Authors: Tao Song Jun-Yi Wang Jiang-Peng Qiu Jia-Qiang Yang Zhao-Yun Wang Yi Zhao Xiao-Hui Yang Ren Hu Jun Cheng Fang-Zu Yang Lian-Huan Han Dong-Ping Zhan

Developing a highly efficient leveler in acid copper electroplating solution is one of the primary tasks necessary for achieving superconformal filling of microvias and interconnections in printed circuit boards (PCBs). Two triethylenediamine-based Gemini levelers, both with terminal quaternary ammonium groups, are synthesized and named as GL1 (C8) after reaction of triethylenediamine with 1,8-dichlorooctane and GL2 (C6 with two C–O linkages) after triethylenediamine with 1,2-bis(2-chloroethoxy) ethane. Electrochemical experiments indicate that at 100 rpm and 1000 rpm GL2 combines with a suppressor and accelerator to exhibit greater potential difference of 23 mV than GL1 in 9 mV for Cu2+ reduction, demonstrating that GL2 has a stronger synergistic convection-dependent adsorption (CDA) effect. Microvias copper electroplating experiments confirm that acid copper electroplating solution containing GL2 achieve more effective superconformal void-free filling as it results in FP = 96.1%, while the solution containing GL1 results in FP = 70%. Theoretical calculations indicate that adsorption energy of GL2 is −1037.54 kJ·mol−1, which is lower than GL1 (−1019.06 kJ·mol−1). GL2 displays lower electron density compared to GL1, which facilitates its displacement by accelerator at the bottom. The lower adsorption energy of GL2 suggests the weaker adsorption ability and the stronger CDA behavior.

Colloids and Interfaces doi: 10.3390/colloids9050061

Authors: Yuqiao Jin Achyut Adhikari

Food-based emulsifiers, derived from natural or edible sources such as soybeans, oats, eggs, milk, and fruits, have gained increasing attention in the food industry due to their clean label appeal, recognition as natural ingredients, and alignment with consumer demand for fewer synthetic additives. These emulsifiers are also valued for their biodegradability, environmental sustainability, and potential nutritional benefits. The food-based compounds have been extensively studied for their functional and physicochemical properties. This review provides a comprehensive overview of recent developments and applications of food-based emulsifiers, with a focus on protein-based, polysaccharide-based, and phospholipid-based emulsifying agents derived from plant and animal sources. The mechanisms, advantages, and disadvantages of the food-based emulsifiers are discussed. Plant-based emulsifiers offer sustainability, wide availability, and cost-efficiency, positioning them as a promising area for research. Combinations of food-based emulsifiers such as polysaccharides, proteins, and phospholipids can be utilized to enhance emulsion stability. This paper evaluates current literature and discusses future challenges and trends in the development of food-based emulsifiers.

Colloids and Interfaces doi: 10.3390/colloids9050060

Authors: Poppy O’Neill Anastasia Stamatiou Ludger Fischer

Glauber’s salt is a promising phase change material for thermal energy storage due to its high latent heat capacity of 234 J/g and melting point of 34 °C, making it well-suited for low-temperature heating applications. However, its practical use has been limited by phase separation and associated loss of performance during repeated thermal cycling. This study aimed to address this limitation through a novel stabilisation approach. The material was encapsulated within an emulsion matrix designed to physically constrain the salt and inhibit separation during melting and to form a phase change dispersion. The phase change dispersion was subjected to 100 controlled heating–cooling cycles whilst monitoring the latent heat capacity and phase transition plateaus. The phase change dispersion retained its thermal properties throughout testing, showing no measurable degradation in storage capacity nor shift in phase transition temperature. These results demonstrate that this encapsulation mechanism can effectively maintain the functional performance of Glauber’s salt under repeated thermal cycling. This approach may form the basis for more durable salt hydrate-based storage media and has potential relevance for applications in building heating, waste heat recovery and renewable energy integration. By improving stability, this method helps unlock the long-term operational viability of phase change materials.

Colloids and Interfaces doi: 10.3390/colloids9050059

Authors: Romain Botella Grégory Lefèvre

Drying is ubiquitous. However, its influence on surface speciation has been seldom studied. Through an in situ Attenuated Total Reflection–Infrared (ATR-IR) spectroscopy analysis of the drying of molybdate solutions on a lepidocrocite particle film, the change in surface speciation is followed. No formation polymolybdates nor precipitate are observed upon drying at pH 8. An in situ washing of the dried solid/solution interface unveils the existence of surface outer-sphere and inner-sphere complexes. Decreasing the molybdate concentration highlights a saturation effect of the surface upon drying. Moreover, the careful analysis of substrate IR bands showed non-uniform drying which is an important insight to understand dehydration chemistry. The remaining molybdate ions at the surface as inner-sphere complexes are present as binuclear monodentate complexes stabilized by sodium.

Colloids and Interfaces doi: 10.3390/colloids9050058

Authors: Ammaeva Shanaz Isaev Abdulgalim Schubert Richard Pankov Ilya Talanov Valery

The contamination of water resources with heavy metals creates problems for using it as a source of drinking water. Adsorption is one of the most promising methods for heavy metal ion removal from natural and wastewater. The process of removing copper (II) from aqueous solutions using SiO2 xerogel as an adsorbent has been studied. The xerogel was thoroughly characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and argon adsorption–desorption isotherms, revealing an amorphous structure with a high surface area (~347 m2/g) and uniform mesoporosity (2–14 nm pore size). The surface chemistry, dominated by silanol groups, was confirmed by XPS analysis. The adsorption process is influenced by electrostatic interactions between the positively charged Cu(II) ions and the negatively charged surface groups, with the optimal performance near neutral pH. Batch adsorption experiments demonstrated that the silica xerogel effectively removes Cu(II) ions from aqueous solutions, with removal efficiency exceeding 99% at pH values above 4.0. The maximum adsorption capacity of copper (II) ions on SiO2 xerogel is 67.5 mg/L.

Colloids and Interfaces doi: 10.3390/colloids9050057

Authors: Chiyuhao Huang Qian Zhou Maoyuan Li Xiaolin Wei Dongqin Li Xin He Weiwei Chen

In this study, liquid-phase plasma electrolysis (LPE) was successfully employed to remove the sizing agent from T800 carbon fiber surfaces. Through systematic investigation of varying arcing voltages (185–215 V) and electrode spacings (10–20 mm), we determined that an optimal combination of 200 V and 10 mm spacing achieved near-complete sizing removal, as confirmed by SEM, TGA, and XPS analyses. Under this condition, plasma bombardment dominated the removal mechanism, eliminating sizing residues while exposing the underlying fiber grooves. TGA further demonstrated that in samples treated at a 10 mm interval, the weight loss of LPE samples before 300 °C was negligible, indicating that the sizing agent had been thoroughly removed. The results of XPS further confirmed the high efficiency of LPE in the removal of sizing agents (C-O bond content from 41.6% to 26.9%), and the retention of C-O also proved that LPE could maintain the surface activity of carbon fibers, confirming the effectiveness of LPE in decomposing the sizing agent. Meanwhile, based on the above test results, an attempt was made to explain the mechanism of LPE in removing sizing agents from the surface of carbon fibers.

Colloids and Interfaces doi: 10.3390/colloids9050056

Authors: Junwei Pan Yunzhou Tang Ziqing Liang Yong Cao Yunjiao Chen

Perilla seed oil (PSO) possesses various physiological functions, such as lowering blood lipids and preventing cancer; however, its poor water solubility, dispersibility, and oxidative stability severely limit its application scope. Epigallocatechin gallate (EGCG) is a natural antioxidant abundant in tea leaves. In this study, PSO–casein–EGCG microemulsions were prepared, and their stability and lipid-lowering effects were evaluated. The results showed that the PSO microemulsion had a particle size of 361.23 ± 14.85 nm, a zeta potential of −20.77 ± 0.68 mV, a polydispersity index (PDI) of 0.17 ± 0.07, and an encapsulation efficiency of 94.3%. PSO microemulsions remained stable at room temperature for 5 days without droplet aggregation. The stability of the microemulsions was good when the NaCl concentration was between 0.1 and 1 mM and the pH was between 5 and 9. PSO microemulsions enhanced the oxidative stability of PSO. Additionally, PSO microemulsions significantly reduced triglyceride levels in Caenorhabditis elegans (77.50%, p < 0.005). Finally, it was found that the average lipid droplet size of ZXW618 mutant nematodes decreased by 41.23% after PSO microemulsion treatment. Therefore, PSO microemulsions may reduce fat accumulation in C. elegans by decreasing lipid droplet size. This provides new insights for advancing the application of PSO in the food processing industry.

Colloids and Interfaces doi: 10.3390/colloids9050055

Authors: Mohit Yadav Nisha Gaur Nitin Wahi Sandeep Singh Krishan Kumar Azadeh Amoozegar Eti Sharma

Multidrug resistance (MDR) is an emerging global health concern worldwide, driving the need for innovative solutions. Herbal approaches are gaining attention and acceptance due to safer profiles and very few side effects. In this study, silver nanoparticles (VN-AgNPs) were synthesized using Vitex negundo, a medicinally valuable plant. A methanolic extract was prepared from Vitex negundo and the phytochemical evaluation confirmed the presence of flavonoids, alkaloids, and terpenoids, with quantitative analysis revealing high total phenolic content (TPC: 23.59 mg GAE/g) and total flavonoid content (TFC: 45.23 mg rutin/g), both maximized under microwave-assisted extraction (MAE). The antioxidant activity was also highest (18.77 mg AA/g). Characterization of the optimized extract by GC–MS identified various bioactive compounds. VN-AgNPs were synthesized using the aqueous leaf extract under specified conditions and were structurally characterized using many techniques and evaluated for antibacterial activity against four bacterial strains. VN-AgNPs exhibited significant antibacterial efficacy with inhibition zones measuring 16 ± 0.87 mm against Bacillus (Gram-positive), 15 ± 0.46 mm against E. coli (Gram-negative), 12 ± 0.64 mm against Pseudomonas (Gram-negative), and 11 ± 0.50 mm against Pectobacterium (Gram-negative plant pathogen). These findings highlight the efficacy of green-synthesized VN-AgNPs as a promising alternative to combat MDR pathogens, paving the way for sustainable and effective antimicrobial strategies.

Colloids and Interfaces doi: 10.3390/colloids9050054

Authors: Maria Sarpietro Debora Santonocito Giuliana Greco Stefano Russo Carmelo Puglia Lucia Montenegro

In this work, bemotrizinol (BMTZ), a broad-spectrum UV-filter, was loaded into nanostructured lipid carriers (NLC) whose lipid matrix contained different oils (isopropyl myristate, decyl oleate, caprylic/capric triglyceride) to assess the effects of the lipid core composition on the properties of the resulting NLC. Subsequently, the effects of incorporating different concentrations of optimized BMTZ-loaded NLC on the technological properties of O/W emulsions (pH, viscosity, spreadability, occlusion factor, in vitro BMTZ release, skin permeation, and in vitro sun protection factor) were assessed. The optimized BMTZ-loaded NLC contained 3.0% w/w of isopropyl myristate and showed mean size = 190.6 ± 9.8 nm, polydispersity index = 0.153 ± 0.013, ζ-potential = −10.6 ± 1.7 mV, and loading capacity = 8% w/w. The incorporation of increasing concentrations (5, 10, 20% w/w) of optimized BMTZ loaded into emulsions provided a slight increase in spreadability, lower viscosity, and no change in pH, occlusion factor, and BMTZ release compared to emulsions containing free BMTZ. No BMTZ skin permeation was observed from all formulations. About a 20% increase in sun protection factor values was obtained for vehicles containing BMTZ-loaded NLC compared with formulations incorporating the same amount of free BMTZ. Therefore, incorporating BMTZ-loaded NLC into emulsions could be a promising strategy to develop safer and more effective sunscreen formulations.

Colloids and Interfaces doi: 10.3390/colloids9040053

Authors: Letícia Sias-Fonseca Paulo C. Costa Lucília Saraiva Ana Alves Maria Helena Amaral

Melanoma is a type of skin cancer with high lethality and increasing incidence. Current treatments typically involve surgery as the first step, followed by adjuvant treatments, which are necessary in most cases. These adjuvant treatments may include radiotherapy, phototherapy, chemotherapy, immunotherapy, and combined therapies. However, patients with melanoma still face great difficulties, such as the inefficiency of therapies and serious side effects, in addition to uncomfortable scars. Most of these problems are related to limitations of antitumor therapies, such as the low bioavailability of drugs, degradation in biological fluids, rapid clearance, difficulty in reaching the tumors, the low capacity for accumulation and infiltration in tumor cells, toxicity to healthy cells, and systemic action. Thus, antitumor therapy for melanoma remains a challenge. In this line, nanotechnology has brought new perspectives and has been the subject of intensive research on the use of nanoparticles (liposomes, lipid nanoparticles, polymeric nanoparticles, inorganic nanoparticles, carbon nanotubes, dendrimers, nanogels, and biomimetic nanoparticles, among others) as carriers for the controlled release of drugs and tumor diagnosis. This work outlines the main limitations of current melanoma therapies and explores how nanoparticle-based drug delivery systems can overcome these challenges, highlighting recent research and clinical developments.

Colloids and Interfaces doi: 10.3390/colloids9040052

Authors: Angelos T. Zamanis Sotiris P. Evgenidis Thodoris D. Karapantsios Margaritis Kostoglou

Foam stability plays a critical role in a wide range of industrial and scientific applications. In this study, an innovative method is presented for assessing foam stability through electrical conductivity measurements of liquid films formed within a controlled experimental setup. A modified horizontal glass capillary system with vertically aligned copper electrodes was developed, allowing the continuous monitoring of film drainage and rupture behavior under precise humidity (92% RH) and temperature (30 °C). Experiments were conducted using various concentrations of sodium dodecyl sulfate and Ethylan 1005, with and without NaCl addition. The results demonstrate that film stability increases with higher surfactant concentrations up to a point, beyond which the addition of salt can have either stabilizing or destabilizing effects depending on whether concentration levels are below or above the Critical Micelle Concentration (CMC). At sub-CMC levels, NaCl enhanced film stability by promoting surfactant adsorption and reducing electrostatic repulsion. Conversely, in super-CMC conditions, NaCl led to film destabilization, likely due to changes in interfacial structure and micellar behavior. This approach provides a simple, sensitive, and reproducible technique to quantitatively characterize foam film stability, offering key mechanistic insights and practical guidance for the formulation and optimization of foaming systems across diverse applications.

Colloids and Interfaces doi: 10.3390/colloids9040051

Authors: Mario Villalobos América Xitlalli Cruz-Valladares

Goethite, a ubiquitous Fe(III) oxyhydroxide mineral, typically occurs in very small particle sizes whose interfacial properties critically influence the fate and transport of ionic species in natural systems. The surface site density of synthetic goethite increases with particle size, resulting in enhanced adsorption capacity per unit area. In the first two parts of this study, we modeled the adsorption of protons, nitrate, As(V), Pb(II), Zn(II), and phosphate on goethite as a function of particle size, adsorbate concentration, pH, and ionic strength, using unified parameters within the CD-MUSIC framework. Here, we extend this work to characterize the interfacial behavior of carbonate in goethite suspensions, using a comprehensive dataset generated previously under both closed and open CO2 system conditions. Carbonate oxyanions, prevalent in geochemical environments, exhibit competitive and complexation interactions with other ions and mineral surfaces. Although a bidentate bridging surface carbonate complex has been successful in previous modeling efforts on goethite, we found that the size of the carbonate moiety is too small and would require extreme octahedron bending of the goethite’s singly coordinated sites to accommodate this type of binding. Here, we propose a novel complex configuration that considers structural, physicochemical, and spectroscopic evidence. Optimal unified affinity constants and charge distribution parameters for this complex simulated all experimental data successfully, providing further validation of the CD-MUSIC model for describing relevant goethite/aqueous interfacial reactions.

Colloids and Interfaces doi: 10.3390/colloids9040050

Authors: Jasminka Kontrec Nives Matijaković Mlinarić Damir Kralj Giuseppe Falini Atiđa Selmani Stefano Goffredo Branka Njegić Džakula

This study investigated the CaCO3 spontaneous precipitation in the presence of soluble organic macromolecules (SOMs) extracted from the skeleton of Mediterranean colonial coral species, symbiotic Cladocora caespitosa (SOM-CCA) and asymbiotic Astroides calycularis (SOM-ACL). This approach was used as a model to explore biomineralization processes in marine organisms. The research was conducted in systems without or with the addition of Mg2+ (Mg/Ca molar ratio was 5:1) and/or SOMs (concentration range was 0.5–4 ppm). In the model system (system without Mg2+ or SOMs), only vaterite spherulites precipitated, while in the system with added Mg2+, only aragonite irregular aggregates were observed. Although the addition of SOMs did not influence the polymorphic composition of the CaCO3 precipitates, it led to noticeable changes in induction time and morphology of CaCO3 crystals, and these effects were stronger in the presence of SOM-ACL. By comparing systems containing both Mg2+ and SOM with the model system as well as with systems where Mg2+ or SOMs were added individually, the dominant role of Mg2+ in the aragonite formation was observed. However, the combined effect of Mg2+ and both SOMs enhanced the inhibition of CaCO3 precipitation. This inhibitory effect was particularly enhanced in the system combining Mg2+ and SOM-ACL.

Colloids and Interfaces doi: 10.3390/colloids9040049

Authors: Qian Lei Lei Rao Wencan Deng Xiuqin Ao Fan Fang Wei Chen Jiaji Cheng Haodong Tang Junjie Hao

Lead sulfide colloidal quantum dots (PbS QDs) have demonstrated great potential in short-wave infrared (SWIR) photodetectors due to their tunable bandgap, low cost, and broad spectral response. While significant progress has been made in surface ligand modification and defect state passivation, studies focusing on the interface between QDs and electrodes remain limited, which hinders further improvement in device performance. In this work, we propose an interface engineering strategy based on 3-aminopropyltriethoxysilane (APTES) to enhance the interfacial contact between PbS QD films and ITO interdigitated electrodes, thereby significantly boosting the overall performance of SWIR photodetectors. Experimental results demonstrate that the optimal 0.5 h APTES treatment duration significantly enhances responsivity by achieving balanced interface passivation and charge carrier transport. Moreover, The APTES-modified device exhibits a controllable dark current and faster photo-response under 1310 nm illumination. This interface engineering approach provides an effective pathway for the development of high-performance PbS QD-based SWIR photodetectors, with promising applications in infrared imaging, spectroscopy, and optical communication.

Colloids and Interfaces doi: 10.3390/colloids9040048

Authors: Ping Li Qiushi Wang

Janus hydrogels, defined by their asymmetric architectures and bifunctional interfaces, have emerged as a transformative class of solid-state electrolytes in electrochemical energy storage. By integrating spatially distinct chemomechanical and ionic functionalities within a single matrix, they overcome the intrinsic limitations of conventional isotropic hydrogels, offering enhanced interfacial stability, directional ion transport, and dendrite suppression in lithium- and zinc-based batteries. This mini-review systematically highlights recent breakthroughs in Janus hydrogel design, including interfacial polymerization and layer-by-layer assembly, which collectively enable precise modulation of crosslinking gradients and ion transport pathways. This review uniquely frames Janus hydrogels from a battery-centric and interface-engineering perspective. It elucidates key structure–function correlations, identifies current limitations in scalable fabrication and electrochemical longevity, and outlines future directions toward intelligent, multifunctional platforms for next-generation flexible and biointegrated energy systems.

Colloids and Interfaces doi: 10.3390/colloids9040047

Authors: Erick Sánchez-Gaitán Ramón Rivero-Aranda Vianney González-López Francisco Delgado

The design of emulsions at the nanoscale is a significant application of nanotechnology. For spherical droplets and a given volume of dispersed phase, the nanometre size of droplets inversely increases the total area, A=3Vr, allowing greater contact with organic and inorganic materials during application. In topical applications, not only is cell contact increased, but also permeability in the cell membrane. Nanoemulsions typically achieve kinetic stability rather than thermodynamic stability, so their commercial application requires reasonable resistance to flocculation and coalescence, which can be affected by temperature changes. Therefore, their thermoresponsive characterisation becomes relevant. In this work, we analyse this response in an O/W nanoemulsion of Palmarosa for antibacterial purposes that has already shown stability for one year at controlled room temperature. We now study hysteresis processes and the behaviour of the statistical distribution in droplet size by Dynamic Light Scattering, obtaining remarkable stability under temperature changes up to 50 °C. This includes a maintained chemical composition observed using Fourier Transform Infrared Spectroscopy and the preservation of antibacterial properties analysed through optical density tests on cultures and the Spread-Plate technique for bacteria colony counting. We obtain practically closed hysteresis curves for some tracers of droplet size distributions through controlled thermal cycles between 10 °C and 50 °C, exhibiting a non-linear behaviour in their distribution. In general, the results show notable physical, chemical, and antibacterial stability, suitable for commercial applications.

Colloids and Interfaces doi: 10.3390/colloids9040046

Authors: Daniel Kim Rajinder Pal

This study presents the first quantitative comparison of catastrophic phase inversion behavior of water-in-oil emulsions stabilized by nanocrystalline cellulose (NCC) and molecular surfactants with different headgroup charge types: anionic (sodium dodecyl sulfate referred to as SDS), cationic (octadecyltrimethylammonium chloride referred to as OTAC), nonionic (C12–14 alcohol ethoxylate referred to as Alfonic), and zwitterionic (cetyl betaine referred to as Amphosol). By using conductivity measurements under controlled mixing and pendant drop tensiometry, this study shows that NCC markedly delays catastrophic phase inversion through interfacial jamming, whereas surfactant-stabilized systems exhibit concentration-dependent inversion driven by interfacial saturation. Specifically, NCC-stabilized emulsions exhibited a nonlinear increase in the critical aqueous phase volume fraction required for inversion, ranging from 0.253 (0 wt% NCC) to 0.545 (1.5 wt% NCC), consistent with enhanced resistance to inversion typically associated with the formation of rigid interfacial layers in Pickering emulsions. In contrast, surfactant-stabilized systems exhibited a concentration-dependent inversion trend with opposing effects. At low concentrations, limited interfacial coverage delayed inversion, while at higher concentrations, increased surfactant availability and interfacial saturation promoted earlier inversion and favored the formation of oil-in-water structures. Pendant drop tensiometry confirmed negligible surface activity for NCC, while all surfactants significantly lowered interfacial tension. Despite its weak surface activity, NCC imparted strong coalescence resistance above 0.2 wt%, attributed to steric stabilization. These findings establish distinct mechanisms for governing phase inversion in particle- versus surfactant-stabilized systems. To our knowledge, this is the first study to quantitively characterize the catastrophic phase inversion behavior of water-in-oil emulsions using NCC. This work supports the use of NCC as an effective stabilizer for emulsions with high internal phase volume.

Colloids and Interfaces doi: 10.3390/colloids9040045

Authors: Elena A. Molkova Ruslan M. Sarimov Tatyana A. Matveeva Alexander V. Simakin Arthur G. Akopdzhanov Dmitriy A. Serov Maksim B. Rebezov Maxim E. Astashev Konstantin V. Sergienko Mikhail A. Sevostyanov Dmitriy O. Khort Igor G. Smirnov Alexey S. Dorokhov Andrey Yu. Izmailov Sergey V. Gudkov

The effect of pH and temperature on the interaction of sodium citrate-coated magnetic iron oxide nanoparticles (IONPs) with the BSA protein was studied using optical methods. The optical properties of aqueous colloids of BSA, IONPs, and BSA with IONPs were studied with pH changes in the range of 2–12 and temperature in the range of 25–85 °C. It was found that at pH 2.0, no significant changes in the optical properties were observed with increasing temperature in aqueous colloids containing a mixture of BSA with IONPs. Temperature affects the optical properties of BSA colloids with IONPs in the pH range from 5.0 to 8.0. Moreover, by increasing the temperature at these pH levels, it is possible to control the particle size in the colloids. In general, both temperature and pH have a significant effect on the properties of the aqueous colloid of BSA with IONPs and allow for the control of interactions between BSA and IONPs, namely, the processes of aggregation, particle reclustering, and protein denaturation.

Colloids and Interfaces doi: 10.3390/colloids9040044

Authors: Ioulia Chikina Michel Beaughon Pierre Burckel Emmanuelle Dubois Ivan T. Lucas Sawako Nakamae Ozlem Sel Hubert Perrot Régine Perzynski Thomas J. Salez Blanca E. Torres-Bautista Andrey Varlamov

Over the last decade, numerous impedance studies of the conductivity of suspensions containing colloidal (dielectric, semiconducting or metallic) particles have often led to the conclusion that the well-known Maxwell theory is insufficient to quantitatively explain the properties of these systems. We review some of the most characteristic results and show how the applicability of the Maxwell’s theory can be restored taking into account the adsorption phenomena occurring during AC impedance measurements in nanoparticle suspensions. The latter can drastically change the capacitance of the metal-electrolyte cell boundaries from the standard value, making it strongly dependent on the nanoparticle concentration. This factor significantly affects conductivity measurements through RC circuit characteristics. We present an analysis of available impedance measurement data of the dependence of conductivity on the nanoparticle concentration in this new paradigm. In order to emphasize the novelty and the acute sensitivity of ac-diagnosis to the presence of adsorption phenomena at the metal-electrolyte interface, direct adsorption determinations at such interfaces by using two modern experimental techniques are also presented. The main result of this work is the restoration of Maxwell’s theory, attributing the observed discrepancies to variations in cell conductance.

Colloids and Interfaces doi: 10.3390/colloids9040043

Authors: Khawla Qamhieh

The mean force between two highly like-charged macroions in the presence of monovalent counterions and added multivalent salt within solvents of varying dielectric constants was studied using Monte Carlo simulations. Without additional salt, the mean force is strongly repulsive at all macroion separations in solvents with a dielectric constant ϵr  ≥ 30. However, in solvents with ϵr ≤ 30, macroions experience effective attraction, indicating that attractive interactions between highly charged macroions can occur even without multivalent salt in nonpolar solvents with low dielectric constants. The total multivalent counterion charge-to-total macroion charge ratio is defined as β which determines the amount of salt that is added to the system. At β = 0.075, the mean force becomes attractive at short separations in solvents with ϵr = 54 containing 1:3 salt, as well as in all solvents with 1:5 salt, while still exhibiting significant repulsion at longer separations. In contrast, for solvents with 1:3 salt and dielectric constants ϵr = 68 and ϵr = 78.4, the mean force turns attractive at a higher salt concentration, around β = 0.225. The shift in the mean force to an attractive state at short separations signifies charge inversion on the macroion surface when a sufficient amount of salt is present. At a stoichiometric ratio of multivalent counterions, long-range repulsion vanishes, and attraction becomes significant. However, with excess salt, the strength of the attractive mean force diminishes. Additionally, the attractive force at a given salt concentration increases as the dielectric constant decreases and is stronger in systems with 1:5 salt than in those with 1:3 salt.

Colloids and Interfaces doi: 10.3390/colloids9040042

Authors: Nazgul Assan Tomoyuki Suezawa Yuta Uetake Yumi Yakiyama Michiya Matsusaki Hidehiro Sakurai

Introducing small-sized metal nanoparticles directly into biopolymers susceptible to thermal and chemical stimulations remains a significant challenge. Recently, we showed a novel approach to fabricating gold nanoparticles through pulsed laser ablation in liquid (PLAL) using a microchip laser (MCL). Despite its lower pulse energy compared to conventional lasers, this technique demonstrates high ablation efficiency, offering the potential to produce composites without compromising the distinctive structure of biopolymers. As a proof of concept, we successfully generated gelatin-stabilized gold nanoparticles with a smaller size (average diameter of approximately 4 nm), while preserving the unchanged circular dichroism (CD) spectra, indicating the retention of gelatin’s unique structure. Extending this technique to the preparation of type I collagen-stabilized gold nanoparticles yielded non-aggregated nanoparticles, although challenges in yield still persist. These results highlight the potential of the microchip laser ablation technique for producing metal nanoparticles within a vulnerable matrix.

Colloids and Interfaces doi: 10.3390/colloids9030041

Authors: Shengzhao Wang Jinfan Song Bin Liu

In this paper, the optical properties and lattice thermal conductivity of Ti2AlB2 were studied by first-principles calculations. The real part of the dielectric constant, ε1, attains a significant value of 47.26 at 0.12 eV, indicating strong polarization capabilities and energy storage capacity. Regarding optical properties, Ti2AlB2 exhibits significant absorption peaks at photon energies of 4.19 eV, 6.78 eV, and 10.61 eV, and 14.32 eV, with absorption coefficients of 184,168.1 cm−1, 228,860.8 cm−1, 366,350.8 and 303,440.6 cm−1, indicating a strong absorption capacity. The loss function exhibits peaks at 19.80 eV and the refractive index reaches a maximum of 8.30 at 0.01 eV. Reflectivity is notably higher in the 0–5 eV range, exceeding 44%, which demonstrates excellent reflective properties. This suggests that Ti2AlB2 has potential as an optical coating material across certain frequency bands. The lattice thermal conductivity of Ti2AlB2 is obtained at 27.2 W/(m·K). The phonon relaxation time is greater in the low-frequency region, suggesting that phonons have a longer duration of action during the heat transport process, which may contribute to higher thermal conductivity. Although the phonon group velocity is generally low, several factors influence thermal conductivity, including phonon relaxation time and Grüneisen parameters. The high Grüneisen parameter of Ti2AlB2 indicates strong anharmonic vibrations, which may enhance phonon scattering and consequently reduce thermal conductivity. However, Ti2AlB2 still exhibits some lattice thermal conductivity, suggesting that the contributions of phonon relaxation time and group velocity to its thermal conductivity may be more significant. The unique optical properties and thermal conductivity of Ti2AlB2 indicate its potential applications in optical coatings and high-temperature structural materials.

Colloids and Interfaces doi: 10.3390/colloids9030040

Authors: Zaichao Dong Rong Zhang Jiyan Chen Chenghao Qu Xin Wang Chen Cong Yang Liu Lingyun Wang

The limited understanding of intermolecular interactions in deep eutectic solvents (DESs) has restricted their rational design and broader application. In this study, a series of hydrophobic DESs (HDESs) were prepared using lidocaine as the hydrogen bond acceptor and various carboxylic acids as hydrogen bond donors. Their physicochemical properties, including density, viscosity, and thermal stability, were systematically characterized. Interactions between components were evaluated through excess molar volume, viscosity deviation, and Grunberg–Nissan parameters. Strong hydrogen bonding between lidocaine and carboxylic acids was confirmed, which weakened with increasing alkyl chain length of the acids. Furthermore, as the acid content in the mixture increased, lidocaine’s ability to disrupt the intrinsic hydrogen-bonding network of the carboxylic acids decreased, thereby weakening the hydrogen bonding interactions between the components. The extraction capability of the HDESs for cobalt ions was evaluated in aqueous systems. Cobalt, a key material in lithium-ion batteries and advanced alloys, is in rising demand due to clean energy development. The lidocaine/decanoic acid (1:2) system exhibited nearly 100% extraction efficiency, surpassing conventional extractants. The hydrophobic nature of the HDESs facilitated effective phase separation and reduced solvent loss. These findings provide theoretical insights and design principles for developing high performance HDESs tailored for environmentally friendly metal recovery, particularly in battery recycling and treatment of industrial wastewater.

Colloids and Interfaces doi: 10.3390/colloids9030039

Authors: Marta Kalbarczyk Sebastian Skupiński Daniel Kamiński Marek Kosmulski

The SAXS pattern and pore volume of SBA-15 are not affected by aging SBA-15 with water, dilute acetic acid, and ammonia up for to 1 month, while the specific surface area is substantially depressed in interactions with basic solutions. The SEM images indicate pits on the side surfaces of SBA-15 particles in interactions with basic solutions. Aging of SBA-15 in ammonia solutions results in cavities formed by the collapse of walls between neighboring hexagonal channels in the SBA-15. This phenomenon is discussed with a special emphasis on its possible effect on the potentiometric titration curves. Especially, a standard procedure, in which the SSA measured before the titration is used to calculate the σ0, is compared with a modified procedure, in which the SSAs measured before and after the titration are used to estimate the SSA for each data point separately.

Colloids and Interfaces doi: 10.3390/colloids9030038

Authors: Qiang Yu Yuxin Mu Pengfei Li Wenjun Zhou Jianwen Zhang Jinchao Li Yong Wei Shanlin Wang

The escalating industrial emissions have dramatically increased airborne particulate matter (PM), particularly submicron particles (PM0.3), creating substantial health risks through respiratory system penetration. Current fiber-based filtration systems predominantly relying on electrostatic adsorption mechanisms suffer from critical limitations, including insufficient efficiency, potential secondary contamination, and performance degradation in humid environments. We develop a flexible silica composite aerogel to overcome these challenges with customizable and exceptional superamphiphobicity. This composite aerogel exhibits high porosity of ~95% and robust compression Young’s modulus that reaches ~220 kPa at 50% strain even after 1000 cycles. These features enable it to maintain a high filtration efficiency of ~98.52% for PM0.3, even after 50 cycles under traditional artificial simulation conditions. Significantly, a competitive filtration efficiency of ~97.9% is still performed in our composite aerogel at high humidity (water mist), high temperatures (50–250 °C), and corrosive solutions or atmospheres environments, revealing potential industrial applications. This work is expected to replace conventional air filtration materials and pave the way for various human protection and industrial production applications.

Colloids and Interfaces doi: 10.3390/colloids9030037

Authors: Yongzhao Feng Xinyi Lin Xiaofang Lai Jikang Jian

SnS1−xSex (x = 0–1) films composed of vertically oriented nanosheet arrays were fabricated by vacuum thermal evaporation. The compositions of the SnS1−xSex films were well tuned from SnS to SnSe, while their structures and morphology maintained the orthorhombic phase and the uniform nanosheet arrays. Se doping enhances the light absorption of the films, especially in the near-infrared region. The direct and indirect band gaps of the SnS1−xSex (x = 0–1) nanosheet arrays films gradually changed from 1.26 eV and 1.12 eV for SnS to 1.00 eV and 0.79 eV for SnSe, respectively, with the change in compositions. The adjustable band gap makes these films promising candidates for infrared photodetectors and solar energy devices.

Colloids and Interfaces doi: 10.3390/colloids9030036

Authors: Danni Luo Wei Sung Ng George V. Franks

Fine spodumene particles are challenging to treat by froth flotation and are often discarded. An approach to recover the lithium-bearing mineral is to selectively aggregate fine spodumene into larger sizes that are amenable to recovery by flotation. This research investigated the aggregation behaviour of spodumene and the gangue minerals K-feldspar and quartz, using commercially available anionic polyacrylamide flocculants. Calcium ions were used as activators that facilitated the selective adsorption of the carboxylate groups in the anionic flocculants onto the spodumene surface. The calcium ions decreased the magnitude of the negative zeta potential and reversed the zeta potential to positive for spodumene and K-feldspar, but not for quartz, below pH 10. Calcium concentrations of 312.5 g/t enhanced the adsorption of anionic polymers onto spodumene and K-feldspar, inducing aggregation, while quartz was aggregated only above 5000 g/t. Increasing the polymer concentration increased the aggregate size for spodumene and K-feldspar, but had little effect on quartz. In situ sizing and turbidity measurements indicated the optimal conditions for spodumene aggregation were 625 g/t of calcium and 63–84 g/t of the 58% anionic-charged polyacrylamide at pH 8.5. The sedimentation results showed limited separation due to quartz entrapment in the aggregates. Anionic polyacrylamide flocculants with calcium activators can aggregate fine spodumene particles.

Colloids and Interfaces doi: 10.3390/colloids9030035

Authors: Hui He Lujia Xuan Yihe Lin Min Zhang Junjie Mou Ruoyang Chen

The evaporation of a blood sessile droplet on a solid substrate generates distinctive desiccation patterns. These patterns have been identified as a potential tool for interpreting the pathological information of donors, since their morphological features encode pathological indicators linked to blood-related disorders. We collected two representative sets of blood samples from anonymous patients: healthy donors (normal haematocrit) and anaemia patients (low haematocrit). Our real-time observations of the morphological evolution during desiccation reveal distinct differences in pattern development. The macroscopic analysis indicates that blood sessile droplets from anaemia patients with abnormally low haematocrit levels experience divergent morphological trajectories, forming cracking patterns distinguishable from those of healthy donors. Our microscopic comparisons show that the blood desiccation patterns of healthy donors exhibit a longer coronal region and greater deposit coverage in the central region than those of anaemia patients. Our further analysis correlates these morphological variations to the effects of the haematocrit level of blood samples on material redistribution. This work proposes a facile strategy for health diagnostics through blood desiccation pattern analysis, highlighting its potential as a foundation for diagnostic platforms.

Colloids and Interfaces doi: 10.3390/colloids9030034

Authors: Iakobson Ivan’kova Nashchekina Vaganov Laishevkina Shevchenko

Currently, for the treatment of corneal diseases (keratitis–corneal opacities), synthetic corneal analogs based on polymer films or hydrogels are being developed. The requirements for the material include biocompatibility, the presence of a developed system of macropores, transparency, rapid swelling, and mechanical strength. Here, with the aim of preparing such materials, a series of gels based on a copolymer of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMP) and 2-hydroxyethyl methacrylate (or vinyl acetate, or ethyl acrylate) were obtained using cryotropic gelation. It was shown that transparent cryogels can be obtained based on the sulfonate-containing comonomer 2-acrylamido-2-methyl-1-propanesulfonic acid at a crosslinking agent concentration of 2.2 mol.%, while the nature of the acrylate comonomer did not show any effect on transparency. It was found that when using AMP and ethyl acrylate, cryogels with a developed system of macropores with a diameter of 50 to 250 μm were formed, and the mechanical strength of such cryogels was sufficient for their subsequent use as corneal implants. Moreover, the PAMP hydrogel containing 2-hydroxyethyl methacrylate or ethyl acrylate units did not affect the viability of cells even after 1 month.

Colloids and Interfaces doi: 10.3390/colloids9030033

Authors: Oleg Korepanov Olga Aleksandrova Anna Botnar Dmitrii Firsov Zamir Kalazhokov Demid Kirilenko Polina Lemeshko Vasilii Matveev Dmitriy Mazing Ivan Moskalenko Alexander Novikov Sviatlana Ulasevich Vyacheslav Moshnikov

Ternary metal chalcogenide quantum dots (QDs), such as CuInS2, have attracted significant attention due to their lower toxicity compared to binary counterparts containing cadmium or lead, making them promising candidates for biomedical imaging and solar energy applications. The surfactant choice is critical for controlling nanocrystal nucleation, growth kinetics, and functionalization. This directly affects the toxicity and applications of QDs. In this work, we report a synthesis protocol for PVP-capped CuInS2 QDs in an aqueous solution. Using density functional theory (DFT) calculations, we predicted the coordination patterns of PVP on the CuInS2 QDs surface, providing insights into the stabilization mechanism. The synthesized QDs were characterized using TEM, XRD, XPS, and FTIR to assess their morphology, chemical composition, and surface chemistry. The QDs exhibited dual photoluminescence (PL) maxima at 550 nm and 680 nm, attributed to defect-related emissions, making them suitable for cell imaging applications. Cytotoxicity studies and cell imaging experiments demonstrate the excellent biocompatibility and effective staining capabilities of the PVP-capped CuInS2 QDs, highlighting their potential as fluorescent probes for long-term, multicolor cell imaging including two-photon microscopy.

Colloids and Interfaces doi: 10.3390/colloids9030032

Authors: Anshika Sharma Arun Singh

Fruits are a significant source of natural nutrition for human health. However, the perishable nature and short shelf life of fruits lead to spoilage, nutrition safety challenges, and other substantial postharvest losses. Edible coatings have emerged as a novel approach in order to enhance the shelf life of perishable fruits by forming a protective barrier against adverse environmental conditions and microbial infections. Sodium alginate is recognized as an excellent polysaccharide (derived from algae, seaweed, etc.) in the food industry for edible fruit coatings because of its non-allergic, biodegradable, non-toxic (safe for human health), inexpensive, and efficient gel/film-forming properties. However, the hydrophilicity of the polysaccharides is a significant concern to prevent the growth of mold and yeast. In recent years, various plant extracts (containing multiple bioactive compounds, including polyphenolic acids) and nanoparticles have been applied in sodium alginate-based edible films and fruit coatings to enhance antimicrobial activity. This review study summarized recent advancements in fabricating plant extracts incorporating sodium alginate-based films and coatings to enhance fruit shelf life. In addition, approaches to preparing edible films and the basic mechanism behind the role of coating materials in enhancing fruit shelf life are discussed. Moreover, the limitations associated with sodium alginate-based fruit coatings and films have been highlighted.

Colloids and Interfaces doi: 10.3390/colloids9030031

Authors: Cao Tuan Anh Dao Tran Cao Luong Truc-Quynh Ngan

Surface-enhanced Raman scattering (SERS) is a powerful technique for detecting trace amounts of chemicals due to its capacity to significantly amplify the Raman signal of the molecules of these substances. This is particularly relevant in food systems where monitoring antibiotic residues is critical for food safety. Traditional SERS substrates typically utilize colloidal silver nanospheres (AgNSs), but anisotropic silver nanoparticles with numerous sharp tips can further enhance SERS sensitivity, enabling lower detection limits suitable for food safety regulations. In this study, we describe a straightforward synthesis of colloidal silver triangular nanoplates (AgTNPls), featuring multiple sharp tips, using only four common reagents: silver nitrate, trisodium citrate, sodium borohydride (NaBH4) and hydrogen peroxide (H2O2), all at room temperature. By carefully controlling the sequence of reagent addition, specifically introducing H2O2 after NaBH4, we achieved a two-step synthesis. In the first step, AgNSs seeds form, and in the second, these seeds convert into AgTNPls, resulting in a colloid of relatively uniform AgTNPls with an edge length of approximately 52 nm. The resulting AgTNPls colloid, combined with an aluminum foil, produced an SERS substrate with high enhancement factor of 3.2 × 109 (using rhodamine 6G as a test molecule). Applied to enrofloxacin (an antibiotic widely used in livestock and aquaculture) detection, this substrate achieved a detection limit as low as 0.39 µg/L (0.39 ppb), with enrofloxacin detectable at concentrations down to 5 µg/L. This highly sensitive SERS substrate holds great promise for rapid, accurate detection of antibiotic residues in food products, aiding regulatory compliance and food safety assurance.