Composite Films Research Articles

Properties of quaternized and cross-linked hydroxyethylcellulose composite films

AbstractAlthough trimetylammonium-2-hydroxypropyl-hydroxyethylcellulose (QHEC) is a well-known polysaccharide material, some of its properties have not been previously studied in detail. Therefore, we applied a combination of multidimensional nuclear magnetic resonance (NMR) in D2O on hydroxyethylcellulose (HEC) and HEC derivatives, and size-exclusion chromatography with multi-angle laser light scattering (SEC-MALS) in carbonate buffer at pH 10; while Fourier-transform infrared spectroscopy (FTIR), the X-ray diffraction (XRD), the thermogravimetry/differential/differential thermogravimetry (TG/DTG/DTA) and atomic force microscopy (AFM) in film form. SEC-MALS revealed various water-solubility of prepared derivatives: HEC (98%) > CHEC (72%) > QHEC (26%) > QCHEC (14%). Due to its substituents, the HEC macromolecule forms coil structures with varying gyration radii: QHEC (38–260 nm) > QCHEC (10–230 nm) > CHEC (21–100 nm) > HEC (23–50 nm). FTIR analysis of all prepared films confirmed their identical structure compared to that observed in liquid form in D2O. Onset temperatures (OT) of films degradation decreased in order: HEC (222 °C) > QCHEC (162 °C) > CHEC (142 °C) > QHEC (141 °C). The X-ray diffraction confirmed residual crystallinity of cellulose II (CII) in all four types of prepared films and was linked to ~ 2% water-insolubility of HEC derivatives revealed by SEC-MALS. Atomic force microscopy (AFM) showed significant differences in surface morphology among the four prepared films with surface roughness of: HEC (25 nm) > QCHEC (5.8 nm) > QHEC (4.2 nm) > CHEC (2.8 nm). Various spherical particles were found in case of HEC, circular depressions/holes approximately 4 μm in diameter were observed in case of QHEC. Except for the HEC, all other films showed granular surface probably due to insoluble components. Based on the mechanisms of quaternization and crosslinking and the results of analysis on water-soluble part and films we could assume that there are similarities in structures between the soluble and insoluble products of the reactions.

Multi-Gradient Bone-Like Nanocomposites Induced by Strain Distribution.

The heterogeneity of bones is elegantly adapted to the local strain environment, which is critical for maintaining mechanical functions. Such an adaptation enables the strong correlation between strain distributions and multiple gradients, underlying a promising pathway for creating complex gradient structures. However, this potential remains largely unexplored for the synthesis of functional gradient materials. In this work, heterogeneous bone-like nanocomposites with complex structural and compositional gradients comparable to bones are synthesized by inducing strain distributions within the polymer matrix containing amorphous calcium phosphate (ACP). Uniaxial stretching of composite films exerts the highest strain in the center, which ceases gradually toward the sides, resulting in the gradual decrease of polymer alignment and crystallinity. Simultaneously, the center with high orientation traps most ACP during stretching due to the nanoconfinement effect, which in turn promotes the formation of aligned nanofibrous structures. The sides experiencing the least strain have the smallest amounts of ACP, characteristic of porous architectures. Further crystallization of ACP produces oriented apatite nanorods in the center with a larger crystalline/amorphous ratio than the sides because of template-induced crystallization. The combination of structural and compositional gradients leads to gradient mechanical properties, and the gradient span and magnitude correlate nicely with strain distributions. Accompanying bone-like mechanical gradients, the center is less adhesive and self-healable than the sides, which allows a better recovery after a complete cutting. Our work may represent a general strategy for the synthesis of biomimetic materials with complex gradients thanks to the ubiquitous presence of strain distributions in load-bearing structures.

Cross‐Scale Interface Engineering for Fabricating Super‐Strong and Super‐Tough Aramid nanofiber film

AbstractPoly (p‐phenylene terephthalamide) (PPTA), known for its exceptional mechanical properties under the brand name Kevlar, finds extensive use in high‐performance applications despite the challenges it presents in processing and integration with other materials. Existing top–down methods for preparing PPTA composites result in significantly reduced strength (<200 MPa) and toughness (<10 MJ·m−3) due to insufficient interfacial interactions, limiting their application. Here, a cross‐scale interface engineering strategy is reported for fabricating super‐strong and super‐tough PPTA composite films. At the microscale, a synergistic crosslinking strategy of physical entanglement and hydrogen bonding to crosslink PPTA nanofibers is employed. At the macroscale, the network using a cyclic freeze–thaw and the stretch‐drying method is reinforced. The PPTA nanofiber composite film is super‐strong (854.6 MPa), super‐tough (106.2 MJ·m−3), and has a high‐temperature resistance (300 °C). Moreover, the bottom–up approach enables the direct synthesis of PPTA nanofibers, significantly reducing the preparation time from 7 days to 0.5 h. Furthermore, it is demonstrated that the composite film can be integrated into a robust and intelligent sensing‐display device that responds to external mechanical and heat injuries for firefighter's protection. This work provides an efficient strategy for fabricating high‐performance PPTA composites, paving the way for their practical use as durable protective materials.

In-situ and ex-situ preparation of Bi2S3 on the BiVO4/TiO2 to construct Bi2S3/BiVO4/TiO2 heterojunction for efficient Cr(VI) reduction

The environmentally friendly and rapid removal of hexavalent chromium (Cr(VI)) from wastewater has garnered significant attention, driven by the severe acute toxicity and carcinogenic properties associated with Cr(VI). The design and synthesis of heterojunctions are recognized as effective solutions for enhancing the photocatalytic performance of TiO2 based materials. BiVO4/TiO2 and Bi2S3/BiVO4/TiO2 composite films (BVT) were prepared via a simple hydrothermal method. The influence of Bi2S3 preparation methods (In-situ and Ex-situ) on the morphology, structure and properties of BVT was studied. The relative crystallinity of TiO2, BiVO4/TiO2, BVT(In-situ) and BVT(Ex-situ) were 50 %, 62 %, 72 % and 92 %, respectively. SEM shows that the morphology of Bi2S3 in BVT(In-situ) was nanoribbon and that of Bi2S3 in BVT(Ex-situ) was radioactive sphere. Compared with pure TiO2 and BiVO4/TiO2, the light absorption range of BVT composite material has been expanded from the ultraviolet light region to the visible region, the bandgap has been significantly narrowed, and the photocurrent density has been increased. The BVT(In-situ) shows stronger photoelectrical performance and reduction efficiency of Cr (VI) compared to BVT(Ex-situ), reaching 93.9 %. The photocatalytic reaction rate of BVT(In-situ) and BVT(Ex-situ) are 0.0291 min−1 and 0.0266 min−1, respectively. Density functional theory (DFT) calculations indicate that the work function of BiVO4 is higher than that of Bi2S3, and electrons will transfer from Bi2S3 to BiVO4 at the heterojunction interface. The BVT(In-situ) heterojunction constructed in this experiment greatly improves the separation and transport efficiency of photo-generated carriers, laying the foundation for the wide application of BVT heterojunction in the field of optoelectronics and providing a strategy for photocatalytic reduction of Cr(VI). The BVT(In-situ) with FTO conductive glass, it also can be applied to photovoltaic fields such as solar cells, photocatalysis and photodetectors.

The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films

Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC).QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials.Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications.

Research Progress on Polysaccharide Composite Films and Coatings with Antioxidant and Antibacterial Ingredients to Extend the Shelf Life of Animal-Derived Meat

Animal-derived meat is rich in proteins and other nutrients, but is prone to spoilage during storage, including microbial contamination and fat oxidation. Therefore, there is an urgent need to find effective solutions to extend the shelf life of animal-derived meat. Polysaccharides are natural macromolecules containing multi-hydroxyl structures and functional groups, which have good solubility, film-forming properties, etc., and can form edible films. Polysaccharide films can be combined with biopolymers, nanoparticles, and natural active agents to improve their properties and enhance the antioxidant and antimicrobial activities of the films. This review summarizes the various sources of polysaccharides, such as chitosan, hyaluronic acid, sodium alginate, carrageenan, starch, and pullulan polysaccharides and their combination with different substances to extend the shelf life of animal-derived meat. This review may serve as a reference for further development of polysaccharides in animal-derived meat preservation.

Tailoring efficient manganese bromide-based scintillator films with ethyl acetate assistance

Metal halide scintillators serve as a compelling substitute for traditional scintillators in X-ray detection and imaging due to their low-temperature fabrication process, high light yield and mechanical flexibility. Nevertheless, the spatial resolution and photoluminescence quantum yield (PLQY) of these films are hindered by the agglomeration and uneven distribution of metal halides crystal particles during the fabrication process. We introduce a modified fabrication approach for metal halide scintillator films involving an additional step of ethyl acetate (EA) treatment, resulting in the preparation of a smooth EA-treated (Ph4P)2MnBr4/Polydimethylsiloxane film. The carbonyl groups within EA interact with elements of the (Ph4P)2MnBr4 microcrystals powder, ensuring uniform dispersion and preventing agglomeration. The EA-treated composite film demonstrates a remarkable PLQY of approximately 95% and an impressive spatial resolution of 14 lp/mm, with enhanced stability under harsh environments. These characteristics ensure its suitability as a high-performance X-ray imaging scintillator.&#xD.

High-Performance Flexible PLA/BTO-Based Pressure Sensor for Motion Monitoring and Human-Computer Interaction.

Flexible electronics show wide application prospects in electronic skin, health monitoring, and human-machine interfacing. As an essential part of flexible electronics, flexible pressure sensors have become a compelling subject of academic research. There is an urgent need to develop piezoelectric sensors with high sensitivity and stability. In this work, the high flexibility of polylactic acid (PLA) film and the excellent ferroelectric properties and high dielectric constant of tetragonal barium titanate (BTO) led to their use as filling materials to fabricate flexible piezoelectric composite films by spinning coating. PLA is used to produce flexible binding substrates, and BTO is added to the composite to enhance its electrical output by improving its piezoelectric performance. The peak output voltage of the PLA/BTO tetragonal piezoelectric film is 22.57 V, and the maximum short-circuit current was 3041 nA. Durability tests showed that during 40,000 s of continuous operation, in the range of 15~120 kPa, the linear relationship between pressure and the film was excellent, the sensitivity for the output voltage is 0.176 V/kPa, and the output current is 27.77 nA/kPa. The piezoelectric pressure sensor (PPS) also enables accurate motion detection, and the extensive capabilities of the PENG highlight its potential in advancing motion sensing and human-computer interactions.

Composite Janus film based on the synergistic interactions of π-π stacking and dynamic covalent bond toward direction recognition sensing

Although flexible strain sensors have made important advancements recently, most of them are unable to recognize the direction of motion, which greatly limits their application in fields such as human-machine interaction. This paper presents the fabrication of a bilayer asymmetric composite film that exhibits Janus dual-sided characteristics and interfacial properties. Specifically, the two sides possess different chemical compositions and surface features. The strong π-π stacking interaction between carbon nanotubes (CNTs) and pyrene enables a tight coating on the surface of poly(glycidyl propyl urethane) (PGPU), resulting in excellent sensing capabilities and electromagnetic shielding properties for the composite material. This composite film can effectively monitor the amplitude and direction of motion. Firstly, pyrene-grafted polyurethane (PGPU) was synthesized including on dynamic covalent bonds. The tensile strength of different samples can reach up to 19.69 MPa, and the strain at break is up to 501.95 %. Furthermore, PGPU/CNTs conductive composite films were fabricated by spray-coating carbon nanotubes (CNTs) onto PGPU, and the pyrene units in PGPU can effectively interact with CNTs via π-π stacking, ensuring that stable adhesion of CNTs layer during long-term usage. Due to the dynamic covalent bonds and hydrogen bonds inside PGPU, PGPU and PGPU/CNTs both exhibit well-performed self-healing capability. Notably, the Janus structure of PGPU/CNTs can adjust the positive and negative values of relative resistance based on stretchable and compressive status of CNTs layer. Thus, PGPU/CNTs are directionally sensitive and self-healing flexible wearable sensor, which might apply in human-machine interaction field.

Influence of substrate temperature on plasma-enhanced chemical vapor deposition to improve the surface flashover performance of epoxy resin

Abstract Epoxy resin composites are widely used as insulating and supporting materials in high-voltage power systems due to their excellent mechanical and electrical properties. However, long-term operation under high-voltage direct current (HVDC) induces surface flashover. Plasma enhanced chemical vapor deposition (PECVD) has been shown to effectively improve the surface insulation properties of epoxy resin. However, the influence of substrate temperature on the film composition, stress, morphology, and surface flashover performance remains unclear. This study uses PECVD to treat epoxy resin, enhancing its surface flashover performance. Tetraethoxysilane (TEOS) is used as the precursor to deposit nano-scale SiOx films on the epoxy resin surface. The effects of different substrate temperatures on the surface flashover voltage, physicochemical properties, and mechanical properties of epoxy resin are characterized. The results show that the surface flashover voltage increases and then saturates with increasing substrate temperature, improving by 27.4% at 60°C compared to untreated samples. The surface roughness of epoxy resin decreases after plasma deposition, while highly oxidized silicon-containing functional groups are introduced. When the substrate temperature increases from 20°C to 60°C, the interfacial bonding strength improves by 25.9%. This study provides a simple, efficient, and controllable method to enhance the surface flashover performance of epoxy resin, promoting the application of this technology in engineering practice.

Augmented barrier properties of poly (lactic acid) composite packaging film reinforced by antibacterial hybrid bio‐filler: Extending the shelf life of fruits

AbstractThis work investigates the construction of biodegradable packaging film based on polylactic acid (PLA) reinforced with a novel antibacterial hybrid nanofiller to improve barrier and mechanical properties. The study focuses on incorporating silver‐ingrained silica particles (Ag–In–Si) into PLA matrix to prepare the packaging film (Ag–In–SiPLA) that has superior antibacterial, and barrier property with negligible oxygen and water vapour penetration. The Ag was synthesized using natural neem leaf extract as a reducing agent. To ingrain silver over rice husk silica (Si) an in situ technique was adopted. Hence called Ag‐In‐Si bio‐filler. The Ag–In–SiPLA films were fabricated using melt blending and sheet extrusion methods by means of a micro‐compounder. The addition of rice husk silica served the purpose of cost‐effectiveness of the packaging film along with the enhancement of the oxygen and water barrier properties of the films. The optimized sample (PLA loaded with 3% Ag–In–Si), exhibited optimum transparency, moisture resistance, and barrier properties compared with control PLA film. The experiments on Muntingia calabura (Jamaica cherry) preservation have verified the remarkable effectiveness of Ag–In–SiPLA films in preserving their quality for an extended period. These biodegradable packaging films, composed of food‐grade materials and sustainable ingredients, have the potential to provide a compostable and environmentally friendly solution for various packaging applications. This research shed light on the antibacterial Ag–In–SiPLA film as a long‐term, high‐performance fruit packaging solution.Highlights Novel antibacterial PLA composite with enhanced barrier and mechanical properties. Silver‐ingrained silica particles improve antibacterial and barrier properties. Green synthesis of silver using neem leaf extract Melt blending and sheet extrusion used to create cost‐effective packaging films. Ag–In–SiPLA films extend Muntingia calabura preservation, proving effective.

A Holistic View of Asphalt Binder Aging under Ultraviolet Conditions: Chemical, Structural, and Rheological Characterization

Asphalt, as a key binder material in road construction, is susceptible to ultraviolet (UV) radiation-induced aging, leading to embrittlement and reduced durability. Despite the significance of UV aging, research in this area remains limited compared to that on thermal aging. This paper comprehensively reviews the current state of research on UV aging in asphalt, focusing on its mechanism, evaluation indicators, and methods to delay or avoid UV aging. The structural components, rheological properties, and aging mechanisms of asphalt are discussed. Various UV aging simulation methods, including the use of UV chambers and accelerated aging tests, are presented along with their evaluation tests such as dynamic shear rheometry, rutting tests, Fourier infrared spectroscopy, and bending beam rheology. Key indicators used to assess UV aging, including physical properties, rheological parameters, and chemical composition changes, are summarized. The mechanisms underlying UV aging, particularly the changes in asphalt’s structural components and rheological properties, are examined. The impact of factors like radiation intensity, temperature, chemical composition, and asphalt film thickness on UV aging is discussed. Additionally, various additives and modifiers, including modified bitumen, UV shielding agents, UV absorbers, antioxidants, and nanomodifiers, are reviewed for their potential to mitigate UV aging. This paper concludes by highlighting the challenges in developing standardized test equipment and evaluation criteria, the limitations of organic modifiers, and the need for further research on nanomaterials to improve asphalt’s UV aging resistance.

Three-layered films enable efficient passive radiation cooling of buildings

Abstract To address the excessive energy consumption of building cooling, the coverage of passive radiation cooling materials on the surface of buildings can effectively save the global refrigeration power resources and reduce the greenhouse gas emissions generated by refrigeration equipment. In this work, passive radiation hydrophobic fabric cooling materials with three functional layers (i.e., top polydimethylsiloxane [PDMS] film layer for solar emissivity, middle polymethylmethacrylate [PMMA] film layer for solar reflectivity, and bottom cotton fabric layer for support) were prepared. This passive radiation cooling material with optimized thickness of PDMS (1.5 mm) and PMMA (3.5 mm) have a rich uneven filament structure and ideal internal bonding structure, which enabled 94% of solar reflectivity and 93.4% of atmospheric window emissivity (8–14 μm). Top layer of the composite film was hydrophobic (a contact angle of 117°) and allowed the rolling of water droplets to remove most of the surface dust. Moreover, these composites presented an excellent cooling of 7.7–15.0°C in the outdoor real cooling test. For medium-sized houses, the roof covered with composite was expected to reduce the emission CO2 by 17% every year. The findings of this work indicated that the prepared three-layered radiation cooling materials have great potentials in thermal energy storage buildings.

Composite PLA films incorporated with micro/nano boron nitride for sustainable food packaging

This study aims to develop polylactic acid (PLA) based composite films with improved mechanical and barrier properties through incorporation of micro boron nitride (BN) and nano boron nitride (NBN). PLA-based films were produced using BN and NBN at varying concentrations (1 – 10% (w/w)), and characterized in terms of physical (color and thickness), mechanical (tensile strength, elongation at break, and heat seal strength), barrier (water vapor transmission rate (WVTR)), antimicrobial, and morphological properties. ΔE and whiteness of the composite PLA films increased, while transparency decreased with increased BN and NBN concentrations. Compared to the control PLA films, the tensile strength of the 1% BN or NBN added films increased by 28% or 40%, respectively. Adding BN and NBN to the PLA matrix significantly reduced the WVTR (p ≤ 0.05). Antimicrobial activity against S. aureus and E. coli was not detected. Multivariate data analysis enabled discrimination of composite PLA films based on simultaneous evaluation of their specific film characteristics. This study reveals the ideal film formulation to produce boron nitride incorporated composite PLA films with proper properties, holding potential to be used as an alternative biodegradable material for sustainable packaging of foods to replace petroleum-based materials.

High-Performance Electro-optical Dual-Mode Color-Changing and Energy Storage Device Based on Mo-Doped WO3 and TiO2/NiO Thin Films.

Under optical and electrical control, a multifunctional electro-optical dual-control color-changing and energy storage device not only realizes fast color conversion but also achieves good energy storage performance. In this work, Mo-doped WO3 (Mo-WO3) films were prepared by a one-step hydrothermal method, among which the 2 at. % Mo-doped WO3 film has the best electrochromic and energy storage performance. Meanwhile, TiO2/NiO composite films were prepared by the hydrothermal method and electrodeposition method. The TiO2/NiO/N719 photoanode was prepared by the dip-dyeing method on the TiO2/NiO composite film. The results show that the TiO2/NiO-10s/N719 composite film has excellent photoelectric conversion and energy storage properties. Finally, choosing Mo-WO3 as the cathode and the TiO2/NiO/N719 film as the anode, a multifunctional electro-optical dual-control Mo-WO3@TiO2/NiO/N719 color-changing and energy storage device was constructed. Under electrical control, it shows a fast color switching rate (the coloring/bleaching time is 4.1/2.9 s), excellent coloration efficiency (62.1 cm2/C), obviously improved area capacitance (90.4 mF/cm2), and excellent cycle stability. Under optical control, it shows a shortened optical response time (the coloring/bleaching is 70.3/158.9 s), excellent coloration efficiency (58.2 cm2/C), better area capacitance (51.1 mF/cm2), and excellent photoelectric conversion efficiency.

Enhanced performance of low-dielectric siloxane-polyimide copolymers: Synthesis and properties

Low-dielectric polyimides (PI) films with outstanding overall performance are attractive for next generation microelectronic applications. Herein, a series of two different FPIs and BPIs derived from 4,4′-diaminodiphenyl ether (ODA) and two different functional dianhydrides, 4,4'-(hexafluoroisopropylidene) biphthalic anhydride (6FDA) and 4,4′-(4,4′-isopropyldiphenoxy) biphthalic anhydride (BPADA), respectively, were synthesized by a conventional two-step methodology that included thermoimidatization. Additionally, employing aminopropyl-terminated polydimethylsiloxane PDMS (molecular weight = 1000) as the source of siloxane-oxygen bonds, a series of polyimide siloxane (SiFPIs and SiBPIs) copolymers were synthesized by varying the siloxane content (ranging from 0 to 5 wt%) within the copolymer structure. The effects of siloxane bond on the thermal, solubility, water resistance, dielectric and mechanical properties of polyimide were investigated systematically. The integration of siloxane significantly enhanced the solubility of these copolymers in polar aprotic solvents (DMAC, DMF, NMP), expanding their applicability in diverse processing environments. Crucially, these copolymers exhibited remarkably low dielectric constants—2.90 for SiFPI at 3% PDMS and 2.92 for SiBPI at 4% PDMS—coupled with low loss values, positioning them as prime candidates for advanced microelectronic applications. All the composite films have high thermal stability near pure PI. The introduction of PMDS into PI can improve the elongation at break and at the same time, the composite films still remained with higher modulus and tensile strength. Extensive hydrophobicity assessments through contact angle and water absorption studies underscored the copolymers’ superior moisture resistance, a critical parameter for their potential deployment in high-performance, environmentally sensitive electronic components.

Applications and Impacts of Edible Coatings on Food Quality

Edible coatings are emerging as a significant trend in the food industry, driven by growing consumer interest in environmental issues, mainly due to concerns about the excessive use of plastics. This study aimed to perform an integrative review to identify the materials used to produce edible films and characterize their applicability for food quality and conservation. For this, the descriptors “edible films” or “edible coatings” and “food quality” or “food preservation” or “food safety” were used in the Science Direct database, resulting in 48 articles selected. Fruits and vegetables are the two food groups most studied with coatings based on hydrocolloids, protein, composite films, and lipids, with a greater emphasis on the positive impacts on their quality and conservation. Animal products have a higher frequency of studied antimicrobial effects. There is a diversity of materials used in coatings: vegetable-based, such as algae, mucilages, and fibers, as well as those of animal origin, such as gelatin and protein hydrolysates. Few studies have addressed sustainability concepts as final characteristics of coatings. In conclusion, edible coatings show promise for the food industry, offering benefits for both food and the environment. However, more studies are needed to fully explore their potential as replacements for conventional plastics, while ensuring safety and regulatory compliance.

Fine structure control of Fe3O4/ Fe2O3 film by Nitridation-Oxidation-Reduction treatment and high corrosion resistance

The nitriding post-oxidation composite treatment is clean and pollution-free, and the high corrosion resistance of the modified layer has aroused extensive research interest. The phase composition and microstructure of Fe3O4/Fe2O3 film are key factors determining corrosion resistance. We propose a Nitridation-Oxidation-Reduction (NOR) treatment technology nitriding followed by oxidation treatment and then reduction treatment. The precise phase composition and microstructure of the oxide film were characterized and analyzed, and the corrosion resistance of the oxide film was evaluated. Through reduction treatment, the Fe3O4 phase content increased from 54.95 % to 84.75 %, the corrosion potential increased by 0.07 V and the corrosion current density decreased by 2.06 × 10-6A. After NOR treatment, the oxide film has extremely high corrosion resistance, which will have important theoretical and engineering application value.

Highly enhanced electrocatalytic OER with facile electrodeposition of MIL–53(Fe)/NiAl–LDH/NF and NiAl–LDH/MIL–53(Fe)/NF

This research investigates a new approach to improve the electrocatalytic rate of the Oxygen Evolution Reaction (OER), a key step in water electrolysis. The study focuses on two promising materials: MIL–53(Fe) and NiAl–LDH. MIL–53(Fe) offers several advantages: high catalytic activity, large surface area, and good chemical stability. NiAl–LDH is attractive due to its layered structure, tolerance to a wide range of pH levels, scalability, and cost-effectiveness. However, their limitations like low conductivity and restricted accessibility of active sites hinder their performance in water splitting applications. To address these limitations, novel composite thin films were created using a technique called layer–by–layer (LBL) electrophoretic deposition. These films, built on nickel foam (NF) substrates, included two configurations: MIL–53(Fe)/NiAl–LDH/NF and NiAl–LDH/MIL–53(Fe)/NF. The MIL-53(Fe)/NiAl-LDH/NF composite exhibited remarkable OER activity in alkaline electrolytes, requiring overpotentials of only 200, 270, and 370 mV to reach current densities of 20, 50, and 100 mA cm−2, respectively. The Tafel slope of 54.86 mVdec−1 suggests rapid reaction kinetics. Additionally, it demonstrated excellent long-term stability, lasting for at least 20 h. The success of the MIL–53(Fe)/NiAl–LDH/NF composite can be attributed to the LBL technique. This method creates a composite with a larger surface area, significantly improving OER efficiency. In contrast, the MIL–53(Fe)/NiAl–LDH/NF configuration had the opposite effect. The NF pores became blocked by the MIL–53(Fe) layer, reducing the overall surface area, hindering electron transfer, and thereby limiting oxygen production. The LBL deposition method used in this study proves its effectiveness in designing efficient electrocatalysts. This opens up possibilities for creating other multicomponent materials for energy applications. The findings provide valuable insights for future research on these promising composite materials, potentially leading to the development of cost-effective and high-performance catalysts for various electrochemical applications.

Structural features of polylactide and natural rubber films produced by solution casting

Composite film samples of polylactide-natural rubber with a rubber content of 5, 10 and 15 wt. % were obtained by the solution method. The study of morphology showed the presence of rubber inclusions in the form of drops in the polylactide matrix. Thermophysical characteristics were determined by differential scanning calorimetry. It was determined that when rubber was added, the peak of cold crystallization of polylactide disappears on melting thermograms, the melting temperature decreases by 1–4°C compared to 100% polylactide. The structure of the obtained compositions was studied by nuclear magnetic resonance, electron paramagnetic resonance, and X-ray diffraction. The diffraction patterns of the samples contain reflections characteristic of the crystalline α-form of polylactide.