Search Results (1,774)

This study investigates the structural and functional enhancement of corn zein–chitosan composites via mild alkaline treatment to develop biodegradable protein-polysaccharide materials for diverse applications. Films with varying zein-to-chitosan ratios were fabricated and characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Both untreated and sodium hydroxide (NaOH)-treated films were evaluated to assess changes in physicochemical properties. FTIR analysis revealed that NaOH treatment promoted deprotonation of chitosan’s amine groups, partial removal of ionic residues, and increased deacetylation, collectively enhancing hydrogen bonding and resulting in a denser molecular network. Simultaneously, partial unfolding of zein’s α-helical structures improved conformational flexibility and strengthened interactions with chitosan. These molecular-level changes led to improved thermal stability, reduced degradation, and the development of porous microstructures. Controlled NaOH treatment thus provides an effective strategy to tailor the physicochemical properties of zein–chitosan composite films, supporting their potential in sustainable food packaging, wound healing, and drug delivery applications. Full article

Photocatalytic composite materials (TiO₂/SiO₂/BFSF) were first fabricated using the sol–gel method of loading SiO₂ and TiO₂ on blast furnace slag fibers (BFSFs) in sequence and using them as a new carrier. Then, TG-DTA, XRD, BET, SEM-EDS, and UV-Vis absorption spectra, as well as spectrophotometric measurements, were employed to analyze the physicochemical properties of TiO₂. The influence of SiO₂ coating, the number of impregnations in TiO₂ sol, the calcination temperature, and the number of repeated usages on the activity of TiO₂/SiO₂/BFSF was researched by analyzing the degradation of methylene blue (MB) aqueous solution. The results show that SiO₂ could increase the load of TiO₂, impede the growth of TiO₂ grains, and inhibit the recombination of electron–hole pairs, ultimately enhancing the photocatalytic activity of samples. The activity of TiO₂/SiO₂/BFSF first quickly increased and then slowly decreased with an increase in the loading times of TiO₂ sol and calcination temperature. After three impregnations in TiO₂ sol and calcining at 450 °C for 2.5 h, a uniform and compact anatase TiO₂ thin film was deposited on the surface of TiO₂/SiO₂/BFSF, showing the strongest activity. When this sample was used to degrade MB aqueous solution for 180 min under ultraviolet light irradiation, the degradation proportion reached a maximum of 96%. After four reuses, the degradation ratio could still reach 67%. In addition, three potential photocatalytic mechanisms were proposed. Finally, the high-value-added application of blast furnace slag for preparing photocatalytic composite materials was achieved, successfully turning solid waste into “treasure”. Full article

Alkyd resins are among the most common coatings used for exterior wood joinery. In Romania, solvent-borne alkyd coatings are widely used to finish wood. The study aims to compare the performance after 7 years of outdoor exposure of two types of alkyd coatings, a semi-transparent brown stain with micronized pigments (Alk1) and an opaque white enamel (Alk2), applied directly on wood or wood pre-treated with three types of resins: acryl-polyurethane (R1), epoxy (R2), and alkyd-polyurethane (R3). Fir (Abies alba) wood served as the substrate. Cracking, coating adhesion, and biological degradation were periodically assessed through visual inspection and microscopy. Additionally, a cross-cut test was performed, and the loss of coating on the directly exposed upper faces was measured using ImageJ. The results indicated that resin pretreatments somewhat reduced cracking but negatively affected coating adhesion after long-term exposure. All samples pretreated with resins and coated with Alk1 lost more than 50% (up to 78%) of the original finishing film by the end of the test. In comparison, coated control samples lost less than 50%. The Alk2 coating exhibited a film loss between 2% and 12%, compared to an average loss of 9% for the coated control. Overall, samples pretreated with alkyd-polyurethane resin (R3) and coated with alkyd enamel (Alk2) demonstrated the best performance in terms of cracking, adhesion, and discoloration. Full article

Polyethylenimine (PEI) is a cationic polymer with a high density of amine groups suitable for strong electrostatic interactions with biological molecules to preserve their bioactivities during encapsulation and after delivery for biomedical applications. This review provides a comprehensive overview of PEI as a drug and gene carrier, describing its polymerization methods in both linear and branched forms while highlighting the processing methods to manufacture PEIs into drug carriers, such as nanoparticles, coatings, nanofibers, hydrogels, and films. These various PEI carriers enable applications in non-viral gene and small molecule drug deliveries. The structure–property relationships of PEI carriers are discussed with emphasis on how molecular weights, branching degrees, and surface modifications of PEI carriers impact biocompatibility, transfection efficiency, and cellular interactions. While PEI offers remarkable potential for drug and gene delivery, its clinical translation remains limited by challenges, including cytotoxicity, non-degradability, and serum instability. Our aim is to provide an understanding of PEI and the structure–property relationships of its carrier forms to inform future research directions that may enable safe and effective clinical use of PEI carriers for drug and gene delivery. Full article

Photovoltaic–thermal (PVT) technology has attracted considerable attention for its ability to significantly improve solar energy conversion efficiency by simultaneously providing electricity and heat during the day. PVT technology serves a purpose in condensers and subcoolers for passive cooling in refrigeration systems at night. In our previous work, we proposed a switchable film-insulated photovoltaic–thermal–passive cooling (PVT-PC) module to address the structural incompatibility between diurnal and nocturnal modes. However, the performance of the proposed module strongly depends on two key design parameters: the structural height and the vacuum level of the air cushion. In this study, a numerical model of the proposed module is developed to examine the impact of design and meteorological parameters on its all-day performance. The results show that diurnal performance remains stable across different structural heights, while nocturnal passive cooling power shows strong dependence on vacuum level and structural height, achieving up to 103.73 W/m² at 10 mm height and 1500 Pa vacuum, which is comparable to unglazed PVT modules. Convective heat transfer enhancement, induced by changes in air cushion shape, is identified as the primary contributor to improved nocturnal cooling performance. Wind speed has minimal impact on electrical output but significantly enhances thermal efficiency and nocturnal convective cooling power, with a passive cooling power increase of up to 31.61%. In contrast, higher sky temperatures degrade nocturnal cooling performance due to diminished radiative exchange, despite improving diurnal thermal efficiency. These findings provide fundamental insights for optimizing the structural design and operational strategies of PVT-PC systems under varying environmental conditions. Full article

Biopolymers and bio-based plastics, such as polylactic acid (PLA) and polybutylene succinate (PBS), are recognized as environmentally friendly materials and are widely used, especially in the packaging industry. The purpose of this study was to assess the degradation of PLA- and PBS-based formulations in the forms of granules and films under controlled composting conditions at a laboratory scale. Biodegradation tests of bio-based materials were conducted under controlled aerobic conditions, following the standard EVS-EN ISO 14855-1:2012. Scanning electron microscopy (SEM) was performed using a high-resolution Zeiss Ultra 55 scanning electron microscope to analyze the samples. After the six-month laboratory-scale composting experiment, it was observed that the PLA-based materials degraded by 47.46–98.34%, while the PBS-based materials exhibited a final degradation degree of 34.15–80.36%. Additionally, the PLA-based compounds displayed a variable total organic carbon (TOC) content ranging from 38% to 56%. In contrast, the PBS-based compounds exhibited a more consistent TOC content, with a narrow range from 53% to 54%. These findings demonstrate that bioplastics can contribute to reducing plastic waste through controlled composting, but their degradation efficiency depends on the material composition and environmental conditions. Future efforts should optimize bioplastic formulations and composting systems while developing supportive policies for wider adoption. Full article

Nanofiltration (NF) is considered a competitive purification method for acidic stream treatments. However, conventional thin-film composite NF membranes degrade under acid exposures, limiting their applications in industrial acid treatment. For example, wet-process phosphoric acid contains impurities of multivalent metal ions, but NF membrane technologies for impurity removal under harsh conditions are still immature. In this work, we develop a novel strategy of acid-resistant nanofiltration membranes based on interfacial polymerization (IP) of polyethyleneimine (PEI) and cyanuric chloride (CC) with the s-triazine ring. The IP process was optimized by orthogonal experiments to obtain positively charged PEI-CC membranes with a molecular weight cut-off (MWCO) of 337 Da. We further applied it to the approximate industrial phosphoric acid purification condition. In the tests using a mixed solution containing 20 wt% P₂O₅, 2 g/L Fe³⁺, 2 g/L Al³⁺, and 2 g/L Mg²⁺ at 0.7 MPa and 25 °C, the NF membrane achieved 56% rejection of Fe, Al, and Mg and over 97% permeation of phosphorus. In addition, the PEI-CC membrane exhibited excellent acid resistance in the 48 h dynamic acid permeation experiment. The simple fabrication procedure of PEI-CC membrane has excellent acid resistance and great potential for industrial applications. Full article

This study analyzes the thermal degradation of PVA and PVA/glycerol films in air under varying heating rates. Thermogravimetric analysis (TGA) of pure PVA in both air and inert atmospheres confirmed that oxidative conditions significantly influence degradation, particularly at lower heating rates. For PVA/glycerol films in air, deconvolution of the differential thermogravimetry (DTG) curves during the main degradation stage revealed distinct peaks attributable to the degradation of glycerol, PVA/glycerol complexes, and PVA itself. Isoconversional methods showed that, for pure PVA in air, the apparent activation energy (Ea) increased with conversion, suggesting the simultaneous occurrence of multiple degradation mechanisms, including oxidative reactions, whose contribution changes over the course of the degradation process. In contrast, under an inert atmosphere, Ea remained nearly constant, consistent with degradation proceeding through a single dominant mechanism, or through multiple steps with similar kinetic parameters. For glycerol-plasticized films in air, Ea exhibited reduced dependence on conversion compared with that of pure PVA in air, with values similar to those of pure PVA under inert conditions. These results indicate that glycerol influences the oxidative degradation pathways in PVA films. These findings are relevant to high-temperature processing of PVA-based materials and to the design of thermal treatments—such as sterilization or pyrolysis—where control over degradation mechanisms is essential. Full article

Grain boundaries are among the most influential structural features that control the charge transport in polycrystalline organic semiconductors. Acting as both charge trapping sites and electrostatic barriers, they disrupt molecular packing and introduce energetic disorder, thereby limiting carrier mobility, increasing threshold voltage, and degrading the stability of organic thin-film transistors (OTFTs). This review presents a detailed discussion of grain boundary formation, their impact on charge transport, and experimental strategies for engineering their structure and distribution across several high-mobility small-molecule semiconductors, including pentacene, TIPS pentacene, diF-TES-ADT, and rubrene. We explore grain boundary engineering approaches through solvent design, polymer additives, and external alignment methods that modulate crystallization dynamics and domain morphology. Then various case studies are discussed to demonstrate that optimized processing can yield larger, well-aligned grains with reduced boundary effects, leading to great mobility enhancements and improved device stability. By offering insights from structural characterization, device physics, and materials processing, this review outlines key directions for grain boundary control, which is essential for advancing the performance and stability of organic electronic devices. Full article

This review synthesized the current knowledge on the effect of TiO₂ photocatalysts on the degradation of microplastics (MPs) and nanoplastics (NPs) under visible light, highlighting the state-of-the-art techniques, main challenges, and proposed solutions for enhancing the performance of the photocatalysis technique. The synthesis of TiO₂-based photocatalysts and hybrid nanostructured TiO₂ materials, including those coupled with other semiconductor materials, is explored. Studies on TiO₂-based photocatalysts for the degradation of MPs and NPs under visible light remain limited. The degradation behavior is influenced by the composition of the TiO₂ composites and the nature of different types of MPs/NPs. Polystyrene (PS) MPs demonstrated complete degradation under visible light photocatalysis in the presence of α-Fe₂O₃ nanoflowers integrated into a TiO₂ film with a hierarchical structure. However, photocatalysis generally fails to achieve the full degradation of small plastic pollutants at the laboratory scale, and its overall effectiveness in breaking down MPs and NPs remains comparatively limited. Full article

Leaves react with rail steel and form a tribofilm, causing very low friction in the wheel/rail interface. This work uses twin-disc tribological testing with the addition of leaf particulates to simulate the reaction and resulting reduction in the friction coefficient in a laboratory setting. Diffuse Reflectance Fourier-Transform Infrared Spectroscopy was carried out on the organic material and the layers that formed on the twin-disc surface. Dark material, visibly similar to leaf layers formed on tracks during autumn, was used along with a transparent thin film. This “non-visible contamination” has been reported to cause low-adhesion problems on railways, but has not previously been characterised. This article discusses the nature of these layers and builds upon earlier studies to propose a degradation and bonding mechanism for the leaf material. This understanding could be used to improve friction management methods employed to deal with low adhesion due to leaves. Full article

Photoelectrochemical devices have garnered extensive research attention in the field of smart and multifunctional photoelectronics, owing to their lightweight nature, eco-friendliness, and cost-effective manufacturing processes. In this work, Bi₂S₃/Bi₂O₃/TiO₂ heterojunction film was successfully fabricated and functioned as the photoelectrode of photoelectrochemical devices. The designed Bi₂S₃/Bi₂O₃/TiO₂ photoelectrochemical photodetector possesses a broad light detection spectrum ranging from 400 to 900 nm and impressive self-powered characteristics. At 0 V bias, the device exhibits an on/off current ratio of approximately 1.3 × 10⁶. It achieves a commendable detectivity of 5.7 × 10¹³ Jones as subjected to a 0.8 V bias potential, outperforming both bare TiO₂ and Bi₂O₃/TiO₂ photoelectrochemical devices. Moreover, the Bi₂S₃/Bi₂O₃/TiO₂ photoelectrode film shows great promise in pollutant decomposition, achieving nearly 97.7% degradation efficiency within 60 min. The appropriate band energy alignment and the presence of an internal electric field at the interface of the Bi₂S₃/Bi₂O₃/TiO₂ film serve as a potent driving force for the separation and transport of photogenerated carriers. These findings suggest that the Bi₂S₃/Bi₂O₃/TiO₂ heterojunction film could be a viable candidate as a photoelectrode material for the development of high-performance photoelectrochemical optoelectronic devices. Full article

Laser annealing of oxide functional thin films makes them compatible with substrates of various types, especially flexible materials. The effects of optical annealing on Ni-doped ZnO thin films were the subject of investigation and analysis in this study. Using pulsed laser deposition, we deposited polycrystalline ZnNiO films on sapphire and silicon substrates. The deposited film was annealed by laser heating. A continuous CO₂ laser was used for this purpose. The uniformly distributed long-wavelength radiation of the CO₂ laser can penetrate deeper from the surface of the thin film compared to short-wavelength lasers such as UV and IR lasers. After growth, optical post-annealing processes were applied to improve the conductive properties of the films. The crystallinity and surface morphology of the grown films and annealed films were analyzed using SEM, and their electrical parameters were evaluated using van der Pauw effect measurements. We used electrical conductivity measurements and investigated the photovoltaic properties of the ZnNiO film. After CO₂ laser annealing, changes in both the crystalline structure and surface appearance of ZnO were evident. Subsequent to laser annealing, the crystallinity of ZnO showed both change and degradation. High-power CO₂ laser annealing changed the structure to a mixed grain size. Surface nanostructuring occurred. This was confirmed by SEM morphological studies. After irradiation, the electrical conductivity of the films increased from 0.06 Sm/cm to 0.31 Sm/cm. The lifetime of non-equilibrium charge carriers decreased from 2.0·10⁻⁹ s to 1.2·10⁻⁹ s. Full article

The accelerated hydrolytic degradation of poly(L-lactide) (PLA)/magnesium (Mg) composite films was investigated to elucidate the influence of surface modification of Mg particles on the degradation behavior and characteristics of PLA composites. Accelerated degradation studies were conducted at 60 °C in a pH 7.4 phosphate-buffered solution over 7 weeks, with degradation monitored using several techniques: mass loss, water absorption, thermal analysis, and Raman spectroscopy. The results indicated that all composite films experienced more than 90% mass loss at the end of experiment; however, PLA/5MgTT and PLA/5MgPEI exhibited the highest resistance to degradation, likely due to the protective effect of the surface modification induced by thermal treatment and polyethylenimine (PEI). Notably, these characteristics did not compromise the biocompatibility or osteogenic potential of the films, which remained comparable to the control samples when tested on human bone marrow multipotent mesenchymal/stromal cells. Full article

The need for renewable and eco-friendly materials is driving the increasing demand for biobased polymers for food applications, with cellulose emerging as a promising option due to its degradability and environmental sustainability. Therefore, in the present study, a strategy to obtain cellulose-based materials with antimicrobial properties was explored by using a selected antimicrobial peptide named RKT1, which was stably and efficiently tethered to cellulose films via physical adsorption, harnessing the high number of functional groups on the polymeric surface. Firstly, the peptide, identified among the previous or new projected compounds, was structurally and functionally characterized, evidencing high conformational stability under a wide range of environmental conditions and efficient antibacterial activity against the foodborne pathogens Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes and the spoilage bacteria Enterococcus and Pseudomonas koreensis, all isolated from meat products. Moreover, in an extended application, the RKT1-activated cellulose films were tested in vivo on beef carpaccio. The results supported their effectiveness in increasing the shelf life of carpaccio by least two days without affecting its organoleptic properties. Therefore, RKT1, physically adsorbed on cellulose, still retains its activity, and the newly generated biopolymers show potential for use as a green food packaging material. Full article