Search Results (9,658)

A surface molecularly imprinted ratiometric fluorescent sensor (Eu/CDs@SiO₂@IIPs) was constructed for the selective and visual detection of Cu²⁺. The sensor integrates blue-emitting carbon dots as an internal reference and a custom-designed Eu(III) complex, Eu(MAA)₂(2,9-phen), as both the functional and fluorescent monomer within a surface-imprinted polymer layer, enabling efficient ratiometric fluorescence response. This structural design ensured that all fluorescent monomers were located at the recognition sites, thereby reducing background fluorescence interference and enhancing the accuracy of signal changes. Under optimized conditions, the sensor exhibited a detection limit of 2.79 nM, a wide linear range of 10–100 nM, and a rapid response time of 3.0 min. Moreover, the uncoordinated nitrogen atoms in the phenanthroline ligand improved resistance to interference from competing ions, significantly enhancing selectivity. Practical applicability was validated by spiked recovery tests in deionized and river water, with results showing good agreement with ICP-MS analysis. These findings highlight the potential of Eu/CDs@SiO₂@IIPs as a sensitive, selective, and portable sensing platform for on-site monitoring of Cu²⁺ in complex water environments. Full article

This work introduces 2-(azulen-1-yldiazenyl)-5-(thiophen-2-yl)-1,3,4-thiadiazole (L) as a functional monomer capable of forming stable, redox-active films with high affinity for lead in aqueous solutions. L was synthesized and characterized using physical chemical methods and electrochemistry. Polymer films of L were prepared through oxidative electro polymerization on glassy carbon electrodes in L solutions in 0.1 M TBAP in acetonitrile. They were characterized through electrochemistry. The surface of chemically modified electrodes (CMEs) prepared through controlled potential electrolysis (CPE) at variable concentrations, potentials, and electric charges was characterized through scanning electron spectroscopy, atomic force microscopy, and Raman spectroscopy, which confirmed the films’ formation. Electrochemical sensing of the films deposited on these CMEs was tested with respect to heavy metal (HM) ion analysis in aqueous solutions to obtain sensors for HMs. The obtained CMEs presented the best characteristics for the recognition of Pb among the investigated HMs (Cd, Pb, Cu, and Hg). Calibration curves were obtained for the analysis of Pb(II) in aqueous solutions, which allowed for the estimation of a good detection limit of this cation (<10⁻⁸ M) for non-optimized CMEs. The resulting CMEs show promise for deployment in portable environmental monitoring systems, with implications for public health protection and environmental safety. Full article

This study explores the enhancement of mechanical properties in cotton yarn-reinforced poly(lactic acid) (PLA) biocomposites, aimed at providing a sustainable alternative to petroleum-based plastics. The primary challenge addressed is the low interfacial shear strength (ISFF) between the hydrophilic cotton yarn and the hydrophobic PLA matrix. To overcome this, cotton yarn surface was chemically modified using silane treatment. Cotton yarns were aligned on a metal frame and treated with hydrolyzed silane solutions at concentrations of 1%, 2%, 3%, and 4% (w/v) for 3 h. Although the tensile stress of the cotton yarn decreased significantly (p < 0.05) with higher silane concentrations, from 520.46 MPa (untreated) to 340.88 MPa (4% silane-treated), the IFSS improved significantly (p < 0.05) from 5.63 MPa to 12.12 MPa. Consequently, the tensile stress of the cotton yarn/PLA biocomposites increased significantly (p < 0.05), from 20.74 MPa (untreated) to 41.58 MPa (4% silane-treated). This is because the increased IFSS achieved through silane treatment allowed the PLA polymer to more firmly connect adjacent cotton fibers, resulting in maximum strength. FTIR and SEM analyses confirmed successful surface modification of the cotton yarn. These findings demonstrate that silane treatment effectively enhances interfacial bonding between cotton yarn and PLA resin, leading to improved mechanical performance of the biocomposites. Full article

Titanium and its alloys are the most widely used metallic materials for bone contact implants. However, despite advances in implant technology, these alloys are still susceptible to post-operative clinical complications such as inflammation, which is often joined by infections and biofilm formation. A number of coatings were studied to overcome the drawbacks of these complications, but the controlled release of bioactive molecules over the first few days and the adhesion of the coating to the substrate remain recognized challenges. Carbon dots and the antibacterial potential of chiral carbon dots (CCDs) were recently reported, and their chirality was identified as a major contribution to the bactericidal effect. This study aimed to achieve a stimuli-responsive medium-term controlled release for up to one month. Two types of chiral carbon dots (CCDs) with distinct functional groups were incorporated into a stable and adherent biodegradable polymer coating, i.e., poly(lactic-co-glycolic acid) (PLGA). To enhance the coating adhesion, the titanium alloy surfaces were pre-treated and activated. The wettability, morphology, and surface composition of the coatings were characterized by contact angle, profilometry, SEM, and XPS, respectively. Coating degradation, adhesion, and CCDs release were studied at physiological pH (7.4) and at an acidic pH characteristic of an inflammatory site (pH 3.0) for up to one month. Their biological performances and blood compatibility were assessed as well. Degradation studies conducted over 28 days revealed a slow mass loss of approximately 10%, with maximum release rates for CCDs-OH and CCDs-NH₂ of 67% and 45% at pH 7.4, respectively. At pH 3.0 an inverse trend was observed with 49% and 59% maximum release after 28 days. Furthermore, the coatings did not exhibit any cytotoxic and hemolytic effects. These findings demonstrate the potential of this approach to providing titanium implants with pH-sensitive controlled release of bioactive CCDs lasting up to one month, which could address key challenges in implant-associated complications. Full article

MXenes, a rapidly emerging family of two-dimensional transition metal carbides and nitrides, have attracted considerable attention in recent years for their potential in next-generation energy storage technologies. In solid-state batteries (SSBs), they combine metallic-level conductivity (>10³ S cm⁻¹), adjustable surface terminations, and mechanical resilience, which makes them suitable for diverse functions within the cell architecture. Current studies have shown that MXene-based anodes can deliver reversible lithium storage with Coulombic efficiencies approaching ~98% over 500 cycles, while their use as conductive additives in cathodes significantly improves electron transport and rate capability. As interfacial layers or structural scaffolds, MXenes effectively buffer volume fluctuations and suppress lithium dendrite growth, contributing to extended cycle life. In solid polymer and composite electrolytes, MXene fillers have been reported to increase Li⁺ conductivity to the 10⁻³–10⁻² S cm⁻¹ range and enhance Li⁺ transference numbers (up to ~0.76), thereby improving both ionic transport and mechanical stability. Beyond established Ti-based systems, double transition metal MXenes (e.g., Mo₂TiC₂, Mo₂Ti₂C₃) and hybrid heterostructures offer expanded opportunities for tailoring interfacial chemistry and optimizing energy density. Despite these advances, large-scale deployment remains constrained by high synthesis costs (often exceeding USD 200–400 kg⁻¹ for Ti₃C₂T_x at lab scale), restacking effects, and stability concerns, highlighting the need for greener etching processes, robust quality control, and integration with existing gigafactory production lines. Addressing these challenges will be crucial for enabling MXene-based SSBs to transition from laboratory prototypes to commercially viable, safe, and high-performance energy storage systems. Beyond summarizing performance, this review elucidates the mechanistic roles of MXenes in SSBs—linking lithiophilicity, field homogenization, and interphase formation to dendrite suppression at Li|SSE interfaces, and termination-assisted salt dissociation, segmental-motion facilitation, and MWS polarization to enhanced electrolyte conductivity—thereby providing a clear design rationale for practical implementation. Full article

Hydrogen energy offers high energy density and carbon-free combustion, making it a promising fuel for next-generation propulsion and power generation systems. Hydrogen offers approximately three times more energy per unit mass than natural gas, and its combustion yields only water as a byproduct, making it an exceptionally clean and efficient energy source. Materials used in hydrogen-fueled combustion engines must exhibit high thermal stability as well as resistance to corrosion caused by high-temperature water vapor. This study introduces a novel ceramic matrix composite (CMC) designed for such harsh environments. The composite is made of yttria-stabilized zirconia (YSZ) fiber-reinforced silicoboron carbonitride [Si(B)CN]. CMCs were fabricated via the polymer infiltration and pyrolysis (PIP) method. Multiple PIP cycles, which help to reduce the porosity of the composite and enhance its properties, were utilized for CMC fabrication. The Si(B)CN precursor formed an amorphous ceramic matrix, where the presence of boron effectively suppressed crystallization and enhanced oxidation resistance, offering superior performance than their counter part. Thermogravimetric analysis (TGA) confirmed negligible mass loss (≤3%) after 30 min at 1350 °C. The real-time ablation performance of the CMC sample was assessed using a hydrogen torch test. The material withstood a constant heat flux of 185 W/cm² for 10 min, resulting in a front-surface temperature of ~1400 °C and a rear-surface temperature near 700 °C. No delamination, burn-through, or erosion was observed. A temperature gradient of more than 700 °C between the front and back surfaces confirmed the material’s effective thermal insulation performance during the hydrogen torch test. Post-hydrogen torch test X-ray diffraction indicated enhanced crystallinity, suggesting a synergistic effect of the oxidation-resistant amorphous Si(B)CN matrix and the thermally stable crystalline YSZ fibers. These results highlight the potential of YSZ/Si(B)CN composites as high-performance materials for hydrogen combustion environments and aerospace thermal protection systems. Full article

Hydrogels comprise three-dimensional networks of hydrophilic polymers and have attracted considerable interest in various sectors, including the biomedical, pharmaceutical, agricultural, and food industries. These materials offer significant benefits for food packaging applications, such as high mechanical strength and excellent water absorption capacity, thereby contributing to the extension of product shelf life. Therefore, the aim of this study is to compare the performance of citric acid and glutaraldehyde as crosslinking agents in gelatine-based hydrogels reinforced with cellulose nanocrystals (CNC), contributing to the development of safe and environmentally responsible materials. The hydrogels were prepared using the casting method and characterised in terms of their physical, mechanical, and structural properties. The results indicated that hydrogels crosslinked with glutaraldehyde exhibited higher opacity, lower transparency, and greater mechanical strength, whereas those crosslinked with citric acid demonstrated improved clarity, reduced water permeability, and enhanced swelling capacity. The incorporation of CNC further improved mechanical strength, reduced weight loss, and altered both surface homogeneity and optical properties. Microstructural results obtained by SEM were consistent with the mechanical properties evaluated (TS, %E, and EM). The Gel-ca hydrogel displayed the highest elongation value (98%), reflecting better cohesion within the polymeric matrix. In contrast, films incorporating CNC exhibited greater roughness and cracking, which correlated with increased rigidity and mechanical strength, as evidenced by the high Young’s modulus (420 MPa in Gel-ga-CNC2). These findings suggest that the heterogeneity and porosity induced by CNC limit the mobility of polymer chains, resulting in less flexible and more rigid structures. Additionally, the DSC analysis revealed that gelatine hydrogels did not exhibit a well-defined Tg, due to the predominance of crystalline domains. Systems crosslinked with citric acid showed greater thermal stability (higher Tm and ΔH_m values), while those crosslinked with glutaraldehyde, although mechanically stronger, exhibited lower thermal stability. These results confirm the decisive effect of the crosslinking agent and CNC incorporation on the structural and thermal behaviour of hydrogels. In this context, the application of hydrogels in packaged products represents an eco-friendly alternative that enhances product presentation. This research supports the reduction in plastic consumption whilst promoting the principles of a circular economy and facilitating the development of materials with lower environmental impact. Full article

In order to form a solid electrolyte interphase (SEI) layer using aqueous processes, a graphite anode called MG-AQP was designed by wrapping and crosslinking graphite particles with aqueous composites (AQCs), which contained zwitterionic polymer, zwitterion molecules, and lithium salts. First, MG-AQP was used to fabricate a full lithium-ion battery (LIB) cell with Li[Ni_0.8Mn_0.1Co_0.1]O₂ (NMC811) as the cathode, denoted as LIB-MG-AQP//NMC811, to demonstrate its performance via a 0.5 C-rate break-in and 1 C-rate cycling. Accordingly, this showed that LIB-MG-AQP exhibits outstanding cyclic stability. To evaluate its electrochemical performance, MG-AQP and lithium metal were used to fabricate a half cell named LIBs-MG-AQP. According to the initial cyclic voltammetry curve, almost no surface reaction for forming an SEI layer exists in LIBs-MG-AQP, illustrating its high initial coulombic efficiency of 92% at a 0.5 C-rate break-in. These outstanding results are due to the fact that the AQC has fewer cracks, thus blocking solvent molecules from passing from the electrolyte into the graphite anode. This study provides new insights to optimize graphite anodes via 0.5 C-rate break-in rather than conventional SEI formation to save time and energy. Full article

The degree of bovine serum albumin (BSA) released from particles based on chitosan and hydroxyapatite prepared by encapsulation and chemisorption methods, crosslinked by aldol condensation, was studied. The obtained materials’ composition was qualitatively determined by IR spectroscopy; phase identification and surface morphology were analyzed by X-ray diffraction and scanning electron microscopy, respectively. A spectrophotometric method was used to quantitatively assess the loading and release degree of encapsulated/chemisorbed BSA from polymer microspheres. To determine the release mechanism, the data on the amount of BSA released were analyzed according to the zero- and first-order, Higuchi, and Korsmayer–Peppas models. Full article

The present study aims to develop 3D-structured adsorbents for carbon capture with the utilization of coal ash after its conversion into zeolites. For this purpose, printing paste mixtures with a viscosity of 800 Pa·s were developed based on an environmentally friendly and safe polymer binder filled with coal ash zeolite with the addition of bentonite as a filler. The optimal consistency of the printing mixtures for preserving the shape and dimensions of the 3D-printed structures was established. Various model configurations of the macrostructure of 3D adsorbents were developed, and the optimal settings of the extruding system for their printing were established. After calcination, the resulting 3D structures were studied using instrumental analysis techniques, investigating the influence of 3D structuring on the phase composition, surface characteristics, and adsorption capacity for CO₂ capture in comparison with the initial powder coal ash zeolite adsorbents. The role of compensating cations in terms of the adsorption ability of powders in 3D-printed adsorbents was investigated. The current study offers an innovative and previously unexplored approach to a more expedient and practically significant utilization of aluminosilicate solid waste and, in particular, coal ash, through their 3D structuring and outlines a new research and technological direction in the development of economically advantageous, technologically feasible, and environmentally friendly 3D adsorbents. Full article

In this work the production of poly(3-hexylthiophene) (P3HT) by electropolymerization using different materials as working electrodes is reported. Initially, the tests were carried out under atmospheric conditions with all the electrodes, and subsequently those that showed the best performance were selected to repeat the experiments in an inert atmosphere. The formation of the polymer film on the electrode surface was characterized by Fourier transform infrared spectroscopy (FT-IR) in the mid-infrared region (4000–400 cm⁻¹). This technique allowed the evaluation of the transmittance of P3HT deposited on the electrode surface. The presence of the polymer was confirmed by the appearance of characteristic absorption bands at 2920 cm⁻¹, 2850 cm⁻¹, 850 cm⁻¹ and 730 cm⁻¹. The absorption peaks found at 2920 cm⁻¹, 2850 cm⁻¹ and 850 cm⁻¹ show the presence of the typical functional groups of P3HT. These results suggest that the proposed method could represent a viable alternative for obtaining semiconductor polymers, avoiding the use of initiators with free radicals potentially harmful to human health. Full article

Basalt fiber reinforced polymer (BFRP) is one of the new materials that can be used for making photovoltaic scaffolds, which can effectively solve the problem of the rapid deterioration of complex environmental performance and high maintenance cost of traditional scaffold materials. This paper focuses on the BFRP photovoltaic support in the cold and arid irrigation area of northwest China, carries out the durability test under the action of chloride salt, freeze-thaw cycle, and chloride salt freeze-thaw environment coupling, and it compares and analyzes the degradation law of the mechanical properties of BFRP sheets under different environmental effects. The performance degradation mechanism of BFRP materials under different environmental effects was revealed by SEM scanning electron microscopy and EDS energy spectrum analysis. The main conclusions are as follows: (1) Under the action of chloride salt, the tensile strength, elastic modulus and elongation at break of the specimen decreased by 11.46%, 7.02%, and 10.27%, respectively. Under the freeze-thaw cycle, the tensile strength and elongation at break of the specimen decreased by 9.62% and 6.85%, while the elastic modulus first increased and then decreased, with a maximum decrease of 12.95%. The degradation of mechanical properties is the most serious under the coupling effect of chloride salt and the freeze-thaw environment. The tensile strength, elastic modulus, and elongation at break of the specimens decreased by 25.73%, 9.55%, and 24.81%, respectively. (2) In the chloride environment, the distribution of elements on the surface of the specimen changed, the metal ions of the fibers precipitated, and ‘black spots‘ and corrosion pits appeared. The resin matrix forms ‘sponge-like‘ pores; under the freeze-thaw cycle, the fiber–resin interface cracks and fiber shedding intensifies; under the coupling effect of chloride freeze-thaw, ‘black spots‘, pits, resin holes, and interface cracks increased, and chloride penetration corrosion accelerated. Full article

Polyvinyl alcohol (PVA), a water-soluble, biodegradable, and biocompatible polymer, has garnered significant attention in recent years for its applications such as packaging, electronics, biomedical materials, and water treatment. However, its high flammability poses a substantial limitation in fire-sensitive environments. To address this challenge, significant research efforts have been devoted to improving the flame retardancy and suppressing the smoke toxicity of PVA through various strategies. This review presents diverse modification strategies that have been developed for PVA, including physical blending with polymers and nanofillers, chemical modifications such as esterification, acetalization, and crosslinking, and advanced surface engineering techniques such as plasma treatment, layer-by-layer assembly, and surface grafting. Beyond fire safety, these modifications enable multifunctional applications, expanding PVA use in optical, energy, sensing, and biomedical fields. Finally, this review explores current challenges, environmental considerations, and future directions for the development of sustainable, high-performance flame-retardant PVA systems. Full article

Developing highly permeable and selective membranes for energy-efficient CO₂/CH₄ separation remains challenging. Mixed-matrix membranes (MMMs) integrating polymer matrices with metal–organic frameworks (MOFs) offer significant potential. However, rational filler–matrix matching presents substantial difficulties, constraining separation performance. In this work, defects were engineered within fluorinated MOF ZU-61 through the partial replacement of 4,4′-bipyridine linkers with pyridine modulators, producing high-porosity HP-ZU-61 nanoparticles exhibiting a 267% BET surface area enhancement (992.9 m² g⁻¹) over low-porosity ZU-61 (LP-ZU-61) (372.2 m² g⁻¹). The HP-ZU-61/6FDA-DAM MMMs (30 wt.%) demonstrated homogeneous filler dispersion and pre-served crystallinity, achieving a CO₂ permeability of 1626 barrer and CO₂/CH₄ selectivity (33), surpassing the 2008 Robeson upper bound. Solution-diffusion modeling indicated ligand deficiencies generated accelerated diffusion pathways, while defect-induced unsaturated metal sites functioned as strong CO₂ adsorption centers that maintained solubility selectivity. This study establishes defect engineering in fluorinated MOF-based MMMs as a practical strategy to concurrently overcome the permeability–selectivity trade-off for efficient CO₂ capture. Full article

This study demonstrates the successful preparation of pristine and modified PVC polymer films with (0.7, 1.0, 2.0, and 3.0 wt%) Cr_1.4Ca_0.6O₄ by the solution casting method. These films were characterized using XRD, FTIR, XPS, SEM, TGA, and a UV–vis spectrophotometer. The XRD confirmed the amorphous nature of PVC films and a tetragonal zircon-type structure of Cr_1.4Ca_0.6O₄ as a dopant in the PVC polymer. The XPS survey spectra of pristine Cr_1.4Ca_0.6O₄ and its composites with PVC reveal essential insights into the materials’ surface composition and chemical states. The spectra clearly show peaks corresponding to O1s, Ca2p, and Cr2p, with the Cr2p signals being notably weaker than the other peaks. SEM images showed a uniform distribution of Cr_1.4Ca_0.6O₄ within the PVC polymer films despite the presence of some minor agglomerations. The TGA analysis revealed that incorporating Cr_1.4Ca_0.6O₄ enhanced the thermal stability of PVC films, particularly at a 0.7 wt% concentration of Cr_1.4Ca_0.6O₄. Moreover, incorporation of Cr_1.4Ca_0.6O₄ improved the optical parameters of PVC films, i.e., linear refractive index, nonlinear refractive index, and optical susceptibility. These findings proposed the modified PVC with Cr_1.4Ca_0.6O₄ for optoelectronic applications. Full article