Search Results (4,667)

The growing concern over the long-term persistence of plastic waste has driven research into biological methods of breaking down polymers. This study investigated a process that combines physicochemical pretreatment and biodegradation of low-density polyethylene (LDPE) using bacterial strains isolated from commercial compost. Four bacterial strains were genetically identified and classified as Actinomycetes. Exposure of LDPE to these selected strains resulted in a measurable reduction in polymer sample weight, accompanied by alterations in surface hydrophobicity. Furthermore, the chemical modifications at the films’ surfaces were confirmed by the spectra obtained by Fourier transform infrared spectroscopy (FTIR). The microbial colonisation of plastic surfaces plays a key role in the overall biodegradation process. The formation of a biofilm and the subsequent morphological changes on the LDPE surface were revealed by scanning electron microscopy (SEM). The modification of the polyethylene surface by nitric acid treatment was found to be a promising strategy for enhancing the LDPE degradation. The acid-treated films exhibited the greatest weight loss, the greatest increase in carbonyl index values, and the greatest change in hydrophobicity following microbial exposure. Moreover, it was found that biodegradation under these conditions resulted in the lowest levels of phytotoxic byproducts. The transformation of polyethylene surface properties—from hydrophobic to hydrophilic—combined with the presence of oxidized functional groups made it easier for microorganisms to degrade LDPE. Full article

Polymer nanocomposites incorporating perovskite (PV) nanoparticles have recently emerged as highly promising materials for optoelectronic and photonic devices. In this work, steady-state and time-resolved photoluminescence (PL) were performed in PV-based polydimethylsiloxane (PDMS) nanocomposite films. The steady-state PL measurements revealed linearly increasing emission as excitation intensities ramped up, followed by a saturation. The optical limiting was scalable through the PV concentrations and is likely due to creation of maximum number of electron–hole (e–h) pairs in the system. The presence of a PDMS altered the multi-exponential PL decay significantly, both in terms of underlying mechanism and the associated timescales. The introduction of PDMS changed a 3-component exponential decay of PV into a 2-component mechanism and reduced the total timescale of decay from 16 ns to ~6 ns. Full article

This work deals with the preparation of a novel set of ternary polymer composites, where the matrix is a cellulose ether and the reinforcement agent is a 50:50 mixture of TiO₂ nanoparticles with PbCl₂ micropowder (0.25–4 wt%). The attained film samples are investigated from morphological, optical, and electrical points of view to explore the applicative potential as LED encapsulants or flexible dielectric layers for capacitors. Morphological analyses at micro- and nanoscale evidence the level of distribution of the fillers blended within the matrix. UV-VIS spectroscopy and refractometry emphasize that at 0.5 wt% the samples display the best balance between transparency and high refractive index, which matches the applicative criteria for LED encapsulation. The electrical testing with broadband dielectric spectrometer proves that the dielectric constant at 1 kHz of the composite with 4 wt% fillers is enhanced by about 6.63 times in comparison to the neat polymer. This is beneficial for designing eco-friendly and flexible dielectrics for capacitor devices. Full article

The growing threat of antimicrobial resistance drives the need for innovative and multifunctional therapeutic systems. In this study, a controlled-release system based on a bioactive film composed of gelatin, bacterial cellulose (BC), sericin, citric acid, PEG 400, and nisin was developed for topical applications in infected wound treatment. BC membranes were produced using Komagataeibacter xylinus and enzymatically treated to optimize dispersion within the polymer matrix. The resulting system exhibited a semi-rigid, homogeneous morphology with appropriate visual characteristics for dermatological use. Microbiological assays demonstrated significant antimicrobial activity against Gram-positive (Staphylococcus aureus) and resistant Gram-negative strains (Escherichia coli and Enterobacter cloacae), attributed to the synergistic action of nisin and citric acid, which enhanced bacterial outer membrane permeability. The antioxidant capacity was confirmed through DPPH radical scavenging assays, indicating a progressive release of bioactive compounds over time. Scanning electron microscopy (SEM) analyses revealed good integration of biopolymers within the matrix. These results suggest that the strategic combination of natural biopolymers and antimicrobial agents produced a functional system with improved mechanical properties, a broadened antimicrobial spectrum, and promising potential as a bioactive wound dressing for the treatment of infected skin lesions. Full article

The majority of the polymeric materials used in the industry are derived from petroleum and decompose slowly, resulting in waste that poses environmental issues. As a result, there has been a concerted effort to find alternative materials that cover their engineering performance. Biopolymers have emerged as leading contenders because they can mimic the properties of synthetic polymers while being derived from natural and renewable sources. Several projects are focused on developing biomaterials for these applications. This study presents a modification of the mechanical properties of a gelatin-based material with the crosslinking agent sodium tripolyphosphate (NaTPP) by reinforcement with agar. The gelatin–agar (G-Ax) samples exhibited a homogeneous color and flexibility, sharing similar crystalline structures and functional groups. However, the transversal section of the gelatin-only film was modified by the addition of agar, from a porous morphology to a lamellar morphology at nanometric scale thickness. Notably, the agar samples demonstrated greater stress resistance, yield stress, and strain than the gelatin-only sample. These findings highlight the potential of biopolymers such as gelatin and agar as viable alternatives to conventional materials, contributing to the research on eco-friendly solutions for different engineering applications. Full article

Ferulic acid (FA) is a bioactive compound known for its potent antioxidant and anti-inflammatory properties; however, its poor water solubility significantly limits its bioavailability and therapeutic potential. In this study, a solid dispersion of FA (FA-SD) was developed using Eudragit^® EPO via the solvent evaporation method, achieving a 24-fold increase in solubility (42.7 mg/mL) at a 1:3 drug-to-polymer ratio. Expandable gastroretentive films were subsequently formulated using starches from Hom-Nil rice, glutinous rice, and white rice, combined with chitosan as the primary film-forming agents, via the solvent casting technique. Hydroxypropyl methylcellulose (HPMC) K100 LV was incorporated as an adjuvant to achieve controlled release. At optimal concentrations (3% w/w starch, 2% w/w chitosan, and 2% w/w HPMC), the films exhibited favorable mechanical properties, swelling capacity, and unfolding behavior. Sustained release of FA over 8 h was achieved in formulations containing HPMC with either Hom-Nil or glutinous rice starch. Among the tested formulations (R6, G6, and H6), those incorporating Hom-Nil rice starch demonstrated the most significant antioxidant (10.38 ± 0.23 μg/mL) and anti-inflammatory (9.26 ± 0.14 μg/mL) effects in murine macrophage cell line (RAW 264.7), surpassing the activities of both free FA and FA-SD. These results highlight the potential of anthocyanin-rich pigmented rice starch-based expandable films as effective gastroretentive systems for enhanced FA delivery. Full article

The development of controlled-release fertilizers (CRFs) has faced significant challenges due to high hydrophilicity and short release lifespan of bio-based materials, as well as non-renewable and high cost of polyester polyols (PPs). In this study, lignin-based polyols (LPs) and PPs were modified to form a cross-linked polymer film on the surface of urea through an in situ reaction. This approach effectively balanced the slow-release ability and environmental protection of controlled-release fertilizer films. A two-factor, five-level orthogonal test was designed for the mass ratio of lignin/polyester polyol and polyol/polyaryl polymethylene isocyanate (PAPI), comprising a total of 25 treatments. The results indicated that the appropriateness of lignin polyols increased the hydrogen bond content of polyurethane membrane, improved the mechanical strength of the fertilizer membrane shell, and effectively reduced friction losses during storage and transportation. Moreover, optimizing the polyol-to-PAPI ratio minimized coating porosity, produced a smoother and denser surface, and prolonged the nitrogen release period. When the lignin polyol dosage was 25% and the polyol to PAPI ratio was 1:2, the nitrogen release time of the prepared coated urea extended to 32 days, which was 3.5 times longer than that of lignin polyurethane coated urea (7 days). The incorporation of lignin and the optimal ratio of coating materials significantly improved the controlled-release efficiency of coated fertilizer, providing theoretical support for the sustainable agricultural application of biomass. Full article

Self-healing coatings can replace conventional coatings and are capable of self-healing and continuing to protect the substrate after coating damage. In this study, two types of self-healing resins were synthesized as coatings: Type-A via Diels–Alder crosslinking of furfuryl-modified diglycidyl ether bisphenol A with bismaleimide, and Type-B through epoxy blending/curing to form a semi-interpenetrating network. FTIR and Raman spectroscopy confirmed the formation of Diels–Alder (DA) bonds, while GPC tests indicated incomplete monomer conversion. Both resins were applied to glass and wood substrates, with performance evaluated through TGA, colorimetry (ΔE), gloss analysis, and scratch-healing tests (120 °C/30 min). The results showed that Type-A resins had a higher healing efficiency (about 80% on glass substrates and 60% on wood substrates), while Type-B resins had a lower healing rate (about 65% on glass substrates and 55% on wood substrates). However, Type-B is more heat-resistant, has a slower decomposition rate between 300 and 400 °C, higher gloss retention, and less color difference (ΔE) between wood and glass substrates. The visible light transmission of Type-B (74.14%) is also significantly higher. Full article

Poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) stands out as a renowned commercial conducting polymer composite, boasting extensive and promising applications in the realm of film electronics. In this study, we have made a concerted effort to overcome the inherent drawbacks of PEDOT:PSS films (especially, high moisture absorption, mechanical damage vulnerability, insufficient substrate adhesion ability, etc.) by uniformly blending them with polydimethylsiloxane polyurea (PDMS-PUa) and silica (SiO₂) nanoparticles through a feasible mechanical stirring process, which effectively harnesses the intermolecular interactions, as well as the morphological and structural characteristics, among the various components. The Si−O bonds within PDMS-PUa and the −CH₃ groups attached to Si atoms significantly enhance the hydrophobicity of the composite film (as evidenced by a water contact angle of 132.89° under optimized component ratios). Meanwhile, SiO₂ microscopically modifies the surface morphology, resulting in increased surface roughness. This composite film not only maintains high conductivity (1.21 S/cm, in contrast to 0.83 S/cm for the PEDOT:PSS film) but also preserves its hydrophobicity and electrical properties under rigorous conditions, including high-temperature exposure (60–200 °C), ultraviolet (UV) aging (365.0 nm, 1.32 mW/cm²), and abradability testing (2000 CW abrasive paper, drag force of approximately 0.98 N, 40 cycles). Furthermore, the film demonstrates enhanced resistance to both acidic (1 mol/L, 24 h) and alkaline (1 mol/L, 24 h) environments, along with excellent self-cleaning and de-icing capabilities (−6 °C), and satisfactory adhesion (Level 2). Notably, the dried composite film can be re-dispersed into a solution with the aid of isopropanol through simple magnetic stirring, and the sequentially coated films also exhibit good surface hydrophobicity (136.49°), equivalent to that of the pristine film. This research aims to overcome the intrinsic performance drawbacks of PEDOT:PSS-based materials, enabling them to meet the demands of complex application scenarios in the field of organic electronics while endowing them with multifunctionality. Full article

This study investigates the effect of polymer film lamination on the tensile performance of wood fiber-reinforced polypropylene (WP) composites. Neat polypropylene (PP) and WP containing 25 wt% wood fiber were injection-molded and laminated with 0.1 mm PP or polyethylene terephthalate (PET) films using a compatible adhesive. Four configurations were examined: unlaminated (0S), single-sided half-length (1S-H), single-sided full-length (1S-F), and double-sided full-length (2S-F). Mechanical properties and fracture morphology were characterized by uniaxial tensile tests and scanning electron microscopy (SEM), alongside measurements of surface roughness. PET lamination produced the greatest strength enhancements, with 2S-F specimens achieving gains of 12% for PP and 21% for WP, whereas PP lamination gave minimal or negative effects, except for a 5% increase in WP. Strength improvements were attributed to surface smoothing and suppression of crack initiation, as confirmed by roughness measurements and SEM observations. PET’s higher stiffness and strength accounted for its superior reinforcement relative to PP. Fractographic analysis revealed flat regions near specimen corners—interpreted as crack initiation sites—indicating that lamination delayed crack propagation. The results demonstrate that PET film lamination is an effective and practical post-processing strategy for enhancing the mechanical performance of wood–plastic composites. Full article

The abuse of quinolone antibiotics in the medical and livestock industries potentially causes environmental accumulation that may impair ecological stability. Based on the organic ligand 5-(pyrazole-1-yl) pyridine-5-yl) terephthalic acid (H₂PPIPA), a terbium(III) complex, [Tb(HPPIPA)(PPIPA)(H₂O)]ₙ (complex 1), was synthesized via solvothermal reaction with Tb(NO₃)₃·6H₂O. Luminescence studies revealed that complex 1 functions as a turn-on fluorescent probe for the selective detection of ofloxacin (OFX), levofloxacin (LFX), and norfloxacin (NFX), with detection limits of 27.9, 17.1, and 8.0 nM, respectively. Owing to its high selectivity and anti-interference capability, the complex was successfully applied for the determination of OFX and LFX in milk samples. Furthermore, a test strip impregnated with complex 1 enabled naked-eye fluorescence detection of OFX, LFX, and NFX under 254 nm UV light. Additionally, a fluorescence sensing film fabricated from complex 1 exhibited excellent recyclability, allowing for at least seven consecutive detection cycles without significant signal loss. This study innovatively designed and synthesized a novel Tb(III)-based coordination polymer fluorescent probe utilizing an original ligand scaffold, achieving the first reported visual detection of quinolone antibiotics with fluorescence test strips and agar films. Full article

Background: The limited aqueous solubility of BCS Class II drugs, exemplified by itraconazole (ITR), continues to hinder their bioavailability and therapeutic performance following oral administration. The present study investigated the development of amorphous solid dispersions (ASDs) of ITR via continuous manufacturing technologies, such as hot melt extrusion (HME) and spray drying (SD), to improve drug release. Methods: Polymer selection was guided by Hansen solubility parameter (HSP) analysis, film casting, and molecular modeling, leading to the identification of aminoalkyl methacrylate copolymer type A (Eudragit^® EPO), polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus^®), and hypromellose acetate succinate HG (AQOAT^® AS-HG) as suitable carriers. ASDs were prepared at drug-to-polymer ratios of 1:1, 1:2, and 2:1. Comprehensive characterization was performed using ATR-FTIR, NMR, DSC, PXRD, SEM, PLM, and contact angle analysis. Results: HME demonstrated higher process efficiency, solvent-free operation, and superior dissolution enhancement compared to SD. Optimized HME-based ASDs were formulated into tablets. The ITR–Eudragit^® EPO formulation achieved 95.88% drug release within 2 h (Weibull model, R² > 0.99), while Soluplus^® and AQOAT^® AS-HG systems achieved complete release, best described by the Peppas–Sahlin model. Molecular modeling confirmed favorable drug–polymer interactions, correlating with the formation of stable complex and enhanced release performance. Conclusions: HME-based continuous manufacturing provides a scalable and robust strategy for improving the oral delivery of poorly water-soluble drugs. Integrating predictive modeling with experimental screening enables the rational design of ASD formulations with optimized dissolution behavior, offering potential for improved therapeutic outcomes in BCS Class II drug delivery. Full article

If untreated, skin wounds can lead to severe complications. Depending on the type of injury, long-term antibiotic administration is often required, and this decreases patient compliance. This limitation could be addressed by applying dressings capable of preventing infections by controlling drug release to the wound site. In this research, biodegradable wound dressings were investigated, based on natural polymers chitosan and alginate and incorporating the broad-spectrum gentamicin as antibiotic. Specifically, gentamicin was loaded into alginate nanoparticles, which were then loaded into chitosan-based films. This approach aimed at obtaining a system capable of modulating antibiotic release. The obtained nanoparticles had an average diameter of 86 nm and polydispersity index of 0.15. Antibiotic loading was around 600 µg/mg, with loading efficiency close to 100%. Films incorporating nanoparticles were compared to control films, which contained only gentamicin. Results showed that nanoparticles incorporation decreased film’s swelling in phosphate buffer saline, thus leading to a decrease in burst release while cytocompatibility for human dermal fibroblasts was maintained. Antibacterial activity was confirmed against both gram-positive and gram-negative bacteria. Moreover, the antibiotic was released as a function of pH, with distinct behavior at pHs ranging from 7.4 to 5.5. This indicates that alginate nanoparticles dispersed in chitosan films effectively release gentamicin on demand. Full article

In this study, the key lithographic performance of PMMA 950K resist was evaluated by exposure to a 30 keV focused gallium (Ga⁺) ion beam. The sensitivity and contrast of PMMA 950K were directly compared with those of electron exposure under identical development conditions. It was found that the sensitivity of PMMA 950K to Ga⁺ ions for 50 nm films reaches a value of about 0.4 μC/cm², which is more than 250 times higher than its sensitivity to electron exposure. A method for evaluating the resist contrast during ion exposure is proposed in this work, taking into account the highly non-uniform dose distribution across the resist depth; it yielded a contrast value of γ = 2.6, which is consistent with the result obtained with electron exposure (γ = 2.8). In addition, a pronounced dependence of the resist sensitivity on the resist thickness was found: with an increase in thickness from 10 nm to 60 nm the sensitivity decreases by an order of magnitude. The obtained results form a reliable methodological basis for characterizing the behavior of polymer resists under ion irradiation and provide valuable recommendations for optimizing lithography with a focused beam of Ga⁺ ions when creating nanostructures for microelectronics, photonics, and quantum technologies. Full article

Hydrogel materials have become an efficient, bioactive, and multifunctional alternative with great potential for biomedical applications. In this work, photoactive films were successfully designed for optical processing, and their photoactivity was tested in photodynamic therapy (PDT), such as antimicrobial patches. The stimulus-response hydrogel films are made of a hydrophilic polymer based on vinyl monomers, specifically 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AAm), in a 1:1 molar ratio, along with the photochromic agent, 3,3-dimethylindolin-6′-nitrobenzoespiropirano (BSP), and a crosslinking agent, N,N’-methylenebisacrylamide (MBA). These hydrogel films were successfully created using the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (IRGACURE 2959), MBA, and BSP in different concentrations (0.1, 0.3, and 0.5 mol%), which were later tested in photodynamic therapy (PDT) with the photosensitizer Ru(bpy)₂²⁺ against Staphylococcus aureus. The results showed that, while free Ru(bpy)₂²⁺ needed concentrations of 4–8 µg/mL to eliminate methicillin-sensitive (MSSA) strains, only partial inactivation was achieved for methicillin-resistant (MRSA) strains. The addition of the hydrogel films with BSP improved their effectiveness, lowering the minimum inhibitory concentration (MIC) to 2 µg/mL to fully inactivate MSSA and MRSA strains. These findings demonstrate that the combined use of hydrogel films containing BSP and Ru(bpy)₂²⁺ within a hydrogel matrix not only boosts antimicrobial activity but also highlights the potential of these photoactive films as innovative photosensitive antimicrobial coatings. This synergistic effect of BSP and Ru(bpy)₂²⁺ indicates that these materials are promising candidates for next-generation antimicrobial coatings and creative photosensitive materials. Full article