Composite Films Research Articles

Interaction between Hydrogen and Magnesium Films: From Hydrogenochromism to Applications.

Hydrogen, as a promising clean energy carrier, underscores the critical need for reliable detection technologies to ensure its safe and efficient use. Magnesium (Mg) thin films, with their hydrogenochromic properties, are particularly well-suited for hydrogen sensing applications due to their dramatic optical transitions. However, practical implementation faces challenges in achieving both rapid response and durability under cyclic conditions. To overcome these limitations, advanced interfacial tuning techniques have been developed to optimize hydrogen diffusion pathways and reinforce structural resilience. This review focuses on the scientific mechanism governing the interaction between Mg-based thin films and hydrogen, highlighting their suitability as hydrogen sensors with superior hydrogenochromic characteristics. Controllable manufacturing methods allow precise control over the alloy composition and microstructure of Mg-based thin films, facilitating the construction of phases and interfaces conducive to support efficient hydride formation, ultimately improving hydrogen response performance. Recent advancements in microstructure engineering, refined in situ characterization techniques, and promising optical applications drive the rapid development of Mg-based thin films.

Optimization of parameters on fig leaf powders added polylactic acid-based composite films using Taguchi method

Optimization of parameters on fig leaf powders added polylactic acid-based composite films using Taguchi method

Desired Color Diversity of Carbon Fiber with Excellent Environmental Super-Durability and Remarkable Flame Retardancy.

Carbon fiber (CF) has been widely used in aerospace, military, infrastructure, sports, and leisure fields owing to its excellent mechanical properties, superior corrosion and friction resistances, excellent thermal stability, and lightweight. However, the ultrablack appearance derived from the extremely strong absorption of light throughout the entire visible region makes it difficult to satisfy the aesthetic and pleasurable demands of the colorful world and limits their applications in a broader field. Herein, inspired by the Japanese jewel beetle, a double-layer ultrathin Al2O3/TiO2 composite structure was fabricated on CFs by the atomic layer deposition method. CFs exhibited desired color diversity by controlling the thickness of Al2O3 and TiO2 films without changing the total thickness of the composite film's structure. Meanwhile, colored CFs have no color change/destruction after a series of environmental durability measurements and exhibited remarkable superdurability and excellent flame retardancy. Our work provides insights for innovative, high-performance, and multifunctional CF that can help achieve high quality and sustainable development of the CF industry.

Photothermal/photodynamic synergistic antibacterial Nanocellulose film modified with antioxidant MXene-PANI Nanosheets.

TEMPO-CNF film modified by two-dimension transition metal MXene has certain antibacterial properties. However, the problem of long-lasting stability greatly restricts the feasibility of long-term use of the composite film. Here, we introduced polyaniline (PANI) as a modifying molecule, which was electrostatically adsorbed on the surface of the MXene nanosheets to prevent its self-stacking and delay its oxidation. The modified MXene could still maintain >85 % stability after 30 days of room temperature storage. The MXene-PANI nanocellulose (MXP/CNF) film was further prepared by combining electrostatic attraction and hydrogen bonding interactions. Thanks to the synergistic effects of the photothermal conversion and photodynamic of MXene and PANI themselves, as well as the high light-trapping properties of the heterostructures, the photothermal and photodynamic efficiencies of the MXP/CNF film were greatly improved. Under the irradiation of 808 nm near-infrared light at 1.5 W/cm2, the MXP/CNF film reached a temperature of 132.9 °C within 20 s. Meanwhile, reactive oxygen species are generated to degrade 55 % of crystalline violet by modified MXene composite film under light irradiation. Compared to 15 % bacterial survival on cellulose film not modified with PANI, S. aureus and E. coli were completely killed on MXP/CNF film under light conditions. The prepared thin film materials exhibit low cytotoxicity, highlighting their potential applications in biomedicine and desalination.

Green preparation of highly transparent nano-NH2-UiO(Zr)-66/cellulose composite films with high-strength, superior flame retardant and UV to high-energy blue light shielding performance.

From the perspective of sustainable development and practical applications, there is a significant demand for the design of advanced cellulose-based film materials with superior mechanical, optical, and functional properties utilizing environmentally friendly strategies. Herein, biodegradable, mechanically robust and flame-retardant cellulose films with adjustable optical performance were successfully fabricated by in situ synthesis of NH2-UiO(Zr)-66 via a DMF-free green process at room temperature. The results indicate that the introduction of NH2-UiO(Zr)-66 enables films to realize a desirable flame retardancy (the limiting oxygen index (LOI) increased significantly from 19.2 % to 32.9 %). The film self-extinguish quickly once removed from the flame, demonstrating a prominent flame resistance. Compared to the original film, the modified films demonstrate a significant reduction in the peak heat release rate and total heat released, decreasing from 186.6 to 26.8 W/g and 19.7 to 1.2 kJ/g, respectively. Encouragingly, the incorporation of nano-NH2-UiO(Zr)-66 enabled films to achieve excellent UV to high-energy blue light (HEBL) shielding competence (90.8-100 %, 99.6-100 %, and 60.9-89 % for UVB, UVA and HEBL) meanwhile retaining low haze (1.9-2.6 %) and high transmittance (86.2-90.9 %). Furthermore, the incorporation of nano-NH2-UiO(Zr)-66 was observed to enhance the mechanical strength. Overall, this film presents a promising alternative to conventional plastics used in various applications, including electronic devices and packaging materials.

Mucilage-based composites films and coatings for food packaging application: A review.

Developing sustainable and eco-friendly packaging solutions has garnered significant interest in recent years. Mucilage-based coatings and composites offer a promising approach due to their biodegradability, renewable nature, and ability to enhance food quality protection. This review paper discusses the impact of mucilage-based composites and coatings on various packaging applications, focusing on their physical, mechanical, morphological, barrier, and functional properties. These materials' adaptability, flexibility, transparency, and compatibility with various food products make them highly suitable for food packaging. The morphological structure of mucilage-based films contributes to improved adhesion, surface roughness, and homogeneity. Enhanced barriers against moisture, oxygen, and other gases extend the shelf life of packaged food while maintaining its quality. Mucilage from different plant sources exhibits functional properties such as antioxidant and antimicrobial activities, which enhance food preservation. These attributes and mucilage's biocompatibility and biodegradability align with the growing demand for environmentally friendly packaging options. The review also addresses cost-effectiveness, regulatory compliance, consumer acceptance, recycling infrastructure compatibility, supply chain considerations, and the need for ongoing innovation. Future advancements in mucilage-based packaging will depend on optimizing performance, scalability, and sustainability. By understanding the effects on physio-mechanical, morphological, barrier, and functional attributes, mucilage-based composites and coatings hold great potential for advancing sustainable food packaging solutions.

PH-responsive composite konjac glucomannan/xanthan gum film incorporated lysozyme fibril for the monitoring of chicken breast freshness.

A pH responsive composite film was developed by incorporating cyanidin (CY) and egg white lysozyme fibril into konjac glucomannan (KGM) and xanthan gum (XG) matrix to monitor the chicken breast freshness in this work. The physicochemical properties of the films, especially pH sensitivity, evaluated by color difference and visual color change under different pH values, were first explored. The freshness changes of chicken breast sealed with the composite films were also analyzed. Hydrogen bonding and electrostatic interaction formed between the components of the composite film. Moreover, the characterizations of pH responsiveness, thermal stability, and barrier property indicated the benefits of incorporating CY and lysozyme fibril into KGM/XG films. The KGM/XG/lysozyme fibril/CY (KXLCY) film showed superior biodegradability in soil. KXLCY composite film reduced the weight loss and delayed the spoilage and fat oxidation rate of chicken breast. In addition, the color of KXLCY film changed from purple red to purple and then to blue during the storage of the packaged chicken breast, indicating a real-time freshness monitoring effect. This work provided a solid scientific foundation for the development of active pH intelligent colorimetric films and their application in food freshness evaluation.

Extraction of lignin from Duabanga grandiflora and its valorization for nanocomposite development with enhanced mechanical and UV shielding properties

Abstract In this study, we report on extracting lignin (EL) from Duabanga grandiflora (Khukon), an untapped wood source, and its transformation into nano-lignin (NL) to create durable and thermally stable composites. Utilizing ultrasonication, we synthesized spherical lignin nanoparticles with an average size of 8 nm, as verified by High-Resolution Transmission Electron Microscopy (HRTEM). These nanoparticles were integrated into a polyvinyl alcohol (PVA) and guar gum (GG) matrix, resulting in PVA-GG-nano-lignin (PGNL) composites. Polyvinyl alcohol (PVA)-Guar gum (GG) nanocomposite films containing various contents of lignin nano-particles (1, 2 and 3 wt%) were formulated by a simple solvent cast method and cross-linked by adding borax. Addition of 1wt% lignin nanoparticles brought in the composite films with 29.8MPa tensile strength and 139.3% elongation at break. Compared to PVA-GG-lignin (PGL) composites, the PGNL composites exhibited a 59.4% increase in tensile strength and enhanced elongation at break and good thermal degradation properties. Notably, the PGNL composite films were transparent but could shield 99.9% of the UV-A (320-400 nm) and UV-B (280-320 nm) radiations, marking a significant advancement in UV protective materials. Our innovative use of Duabanga grandiflora-derived nano-lignin in a dual-polymer network not only underscores the potential of renewable resources in high-performance applications but also aligns with the principles of a circular bioeconomy by offering a sustainable solution for effective UV protection.

Efficient Carbon-Based Optoelectronic Synapses for Dynamic Visual Recognition.

The human visual nervous system excels at recognizing and processing external stimuli, essential for various physiological functions. Biomimetic visual systems leverage biological synapse properties to improve memory encoding and perception. Optoelectronic devices mimicking these synapses can enhance wearable electronics, with layered heterojunction materials being ideal materials for optoelectronic synapses due to their tunable properties and biocompatibility. However, conventional synthesis methods are complex and environmentally harmful, leading to issues such as poor stability and low charge transfer efficiency. Therefore, it is imperative to develop a more efficient, convenient, and eco-friendly method for preparing layered heterojunction materials. Here, a one-step ultrasonic method is employed to mix fullerene (C60) with graphene oxide (GO), yielding a homogeneous layered heterojunction composite film via self-assembly. The biomimetic optoelectronic synapse based on this film achieves 97.3% accuracy in dynamic visual recognition tasks and exhibits capabilities such as synaptic plasticity. Experiments utilizing X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirms stable π-π interactions between GO and C60, facilitating electron transfer and prolonging carrier recombination times. The novel approach leveraging high-density π electron materials advances artificial intelligence and neuromorphic systems.

Investigation of microbial induced calcium carbonate and struvite co-precipitation on cementitious material surfaces.

Microbial-induced carbonate precipitation (MICP) has garnered increasing attention in the realm of building materials. Among them, urease microorganisms have been extensively investigated due to their favorable attributes, including facile reaction control, heightened mineralization efficiency, and straightforward microorganism cultivation. Nevertheless, the presence of ammonia byproducts throughout the reaction process significantly restricted its extensive utilization. This work employed the application of microbial-induced carbonate precipitation (MICP) technology to modify the surface of cement-based materials in a solution environment. Simultaneously, the generation of struvite (MgNH4PO4•6H2O) was induced to eliminate ammonia byproducts and improve the cementitious ability of the film layer. The potential synergistic impact between calcium carbonate (CaCO3) and struvite was observed, resulting in the production of a composite film with enhanced performance. Furthermore, the elimination efficacy of ammonia byproducts was found to exceed 90% after a treatment duration of 96h.

Optical Fiber Hydrogen Sensor Based on π-Phase-Shifted Grating and Sputtered Pd/Hf Composite Film

A novel optical fiber hydrogen sensor based on the π-phase-shifted grating and partial coated Pd/Hf composite film is proposed and experimentally demonstrated in this paper. The hydrogen sensitive Pd/Hf film with the length of 4 mm is successfully deposited in the π-phase-shifted grating region by the magnetron sputtering process and rotating fixture technology. Since the hydrogen sensitivity between the notch and flank wavelengths of the π-phase-shifted grating is different due to the partial coating only on the π-phase-shifted grating region, the relative shift between the notch and flank wavelengths is employed to characterize the hydrogen concentration in this paper. The hydrogen calibration results show that the sensor shows the good response and repeatability. At the temperature of 20 °C and the hydrogen concentration of 2%, the wavelength distance shifts of 200 nm and 500 nm Pd/Hf coatings are 12.6 pm and 33.5 pm, respectively.

Preparing a Composite Nanofiber Film Using Carbon Nanotubes and Polycaprolactone by Electrospinning Method

Preparing a Composite Nanofiber Film Using Carbon Nanotubes and Polycaprolactone by Electrospinning Method

The Effect of Zeolite Na-X and Clinoptilolite as Functional Fillers on the Mechanical, Thermal and Barrier Properties of Thermoplastic Polyurethane.

To obtain sustainable food packaging materials, alternatives to traditional ones must be researched. In this work, two different kinds of zeolites, i.e., a natural one, Clinoptilolite, and a synthetic one, Zeolite Na-X, were mixed with thermoplastic polyurethane for the fabrication of composites. Composite films were prepared via a hot mixing stage and then by means of a hot compression molding process. Several TPU/zeolite composites were produced with a filler concentration ranging from 5% to 10%wt. Finally, the obtained films were characterized by Fourier Transform Spectroscopy (FT-IR, ATR), thermal analysis (TGA and DSC), frequency sweep test, scanning electron microscopy (SEM), mechanical tensile test and oxygen permeability test. For both fillers and at all concentrations, the inclusion of zeolites significantly influenced the analyzed properties. In the TPU/zeolite composites, an overall enhancement was observed compared to the neat polymer, attributed to improved processability, superior barrier properties and the potential to create active materials by loading zeolite combined with various chemicals for specific applications. These findings suggest that the resulting composites hold considerable promise for applications in the food packaging sector.

Scalable, Flexible, and UV-Resistant Bacterial Cellulose Composite Film for Daytime Radiative Cooling.

Radiative cooling, a passive cooling technology, functions by reflecting the majority of solar radiation (within the solar spectrum of 0.3-2.5 μm) and emitting thermal radiation (within the atmospheric windows of 8-13 μm and 16-20 μm). Predominantly, synthetic polymers are effectively utilized for radiative cooling while posing potential environmental hazards due to their complex components, toxicity, or nonbiodegradation. Bacterial cellulose, a natural and renewable biopolymer, stands out due to its environmentally friendly, scalability, high purity, and significant infrared emissivity. In this work, we developed a bacterial cellulose-based composite film (BCF) with a cross-linked network structure by a facile agitation spraying method to achieve enhanced and sustainable radiative cooling performance. The BCF exhibited superior optical properties and environmental tolerance, with a notable infrared emissivity of 94.6%. As a result, the thermal emitter demonstrates a substantial subambient cooling capacity (11:00 to 13:00, maximum drop of 7.15 °C, average drop of 4.85 °C; 22:00 to 2:00, maximum drop of 2.7 °C, average drop of 2.32 °C). Additionally, the BCF maintained stable emissivity after 240 h of continuous UV irradiation. Furthermore, BCF can effectively preserve the freshness of fruits under intense solar irradiation. Hence, BCF with high radiative cooling performance presents a broad application prospect in building energy conservation, solar cells efficiency enhancement, and food transportation packaging.

Chitosan-based films with excellent flame retardancy and highly sensitive fire response for application in self-powered dual fire alarm systems.

The widespread use of flammable building materials severely threatens residential safety. Additionally, traditional fire-alarm systems may fail in complex fire environments due to power disruptions. It is crucial to enhance the flame retardancy of material while establishing effective fire detection and early warning systems. This study prepared a chitosan/gelatin (CG) and LiBr-modified CG (CG-LiBr) composite film using an environmentally friendly water evaporation method. We coated the CG-LiBr film with polytetrafluoroethylene (PTFE), thus a flame-retardant and conductive PTFE-coated film-based triboelectric nanogenerator (PF-TENG) was developed. Notably, the CG-LiBr film exhibits outstanding alarm capabilities, with response times of 0.41 s at 100 °C and 0.4 s under flame attack. Compared to the initial CG, CG-LiBr shows a 24.4 % increase in char residue and a 62.1 % reduction in peak heat release rate. Furthermore, PF-TENG demonstrates excellent voltage output, achieving up to 60.8 V at a vertical contact-separation frequency of 5 Hz. Integrating CG-LiBr's exceptional dual-alarm function into fire protection suits and building materials, along with the development of a fire-alarm system featuring remote signal transmission capabilities, holds considerable promise for enhancing fire safety and developing intelligent early warning systems.

Improvement of the Thermoelectric Properties in CNT/Bi2Te3 Composite Films Due to Evolution of the Depletion Layer and Point Defects under the Pulse Current Field.

A carbon nanotube (CNT) composite is an effective method to improve the thermoelectricity of materials. However, the depletion layer between the CNT and thermoelectric (TE) material always decreases the contribution of CNT to the conductivity of the TE material. It is important to eliminate the depletion layer for improving the TE properties. Pulsed-electric-field (PEF) treatment was used to eliminate the depletion layer based on the atomic short-range diffusion on the interface of CNT and Bi2Te3. When the pulse current density is 30 A·dm-2, the CNT composite Bi2Te3 film has high mobility, a high carrier concentration, and a high effective mass due to no depletion layer and a low density of point defects. Both the resistivity and Seebeck coefficient improve in the CNT composite Bi2Te3 films by PEF treatment of 30 A·dm-2. The power density is 1.36 W·m-2 when the hot side temperature is 373 K. The maximum ZT value of this film is 1.66 at 513 K. Thus, the PEF is an effective way to achieve TE property enhancement in the composite films.

Boosting Thermal Generation in Cation-Exchanged Transparent MXene Composite Films with Hierarchical Wrinkled Structure.

Efficient thermal generation from solar/electric energy in transparent films remains challenging due to the limited toolbox of high-performance thermal generation materials and methods for microstructure engineering. Here, we proposed a two-step strategy to introduce hierarchical wrinkles to the MXene composite films with high transparency, leading to upgraded photo/electrothermal conversion efficiency. Specifically, the thin film contains protic acid-treated MXene layers assembled with Ag nanowires (H-MXene/Ag NWs). The hydrogen-bonding interaction between MXene and Ag NWs in a MXene-based thin film forms the first-level wrinkles, while the cation-exchanged method is then developed to enhance conductivity and form the second-level wrinkles. The H-MXene/Ag NWs composite transparent film is observed to achieve a surface temperature rise of 40 °C relative to an ambient environment under 1.0 sun illumination and 70 °C at 1 V voltage in the dark, along with notable photo/electrothermal production stability under ambient conditions. Moreover, experimental and theoretical results show that the improved heat production capability is mainly due to low reflectivity led by the wrinkles and high conductivity led by the cation-exchange process. On the basis of the excellent photothermal generation capability of the H-MXene/Ag NWs composite transparent film, we applied it to biomimetic soft robots and flexible wearable devices. This work paves a novel strategy for the generation of thermal production devices that achieve high-performance photo/electroconversion.

Optical properties of polyvinyl alcohol-glass waste powder composites

This study investigates the effect of glass waste powder content on the UV–Vis spectroscopy of polyvinyl alcohol (PVA). The glass powder was obtained from the waste of fluorescent tubes. The solution casting method was utilized to prepare PVA- glass composite films by adding glass powder with 10, 20, 30, and 40 wt. %. UV–Vis absorption spectra of PVA- glass samples were recorded in the range 220–1100 nm. The optical parameters were calculated as follow: absorbance, absorption coefficient, transmittance, refractive index, extinction coefficient, dielectric constant, and imaginary dielectric constant. Based on the XRD results, it is revealed that the PVA become more amorphous with increasing amount of glass waste. UV–Vis spectroscopy studies demonstrated that, for all samples, the absorbance, absorption coefficient, extinction coefficient, and Ei increases with the increase in the amount of glass waste. On the other hand, transmittance decreases with increasing amount of glass waste. The change of the studied properties with wavelength depends strongly on the amount of glass waste powder. At visible region, the transmittance is stable with increasing wavelength for samples containing 20, 30 and 40%. Glass waste, while the pure sample and the sample containing 10% glass waste, the transmittance increases with the wavelength. On the other hand, the absorbance and absorption coefficient for all samples decreases rapidly up to a specific wavelength and then the change is very slight at longer wavelengths. Also, the increase of extinction coefficient and imaginary dielectric constant with wavelength is related to the amount of glass powder added. The change of dielectric constant and refractive index with wavelength depends on the amount of the filler, where the pure and the sample filled with 10% glass powder show normal dispersion, while the other samples show anomalous dispersion. Finally, the pure sample had the highest energy gap (5.7 eV) while the sample containing 30% glass powder had the lowest value (4.8 eV). Through this study, it become possible to change the optical properties of PVA by adding glass waste powder, which allows the possibility of benefiting from the new composites to be used in different applications according to their response to different wavelengths. From an economic and environmental point of view, these wastes can be utilized instead of being thrown away by reusing them as polymer fillers, taking into consideration the change in the optical properties of the matrix polymer.

Interfacial modulation and optimization of the electrical properties of ZrGdO x composite films prepared using a UVO-assisted sol-gel method.

In this paper, Gd-doped ZrO2 gate dielectric films and metal-oxide-semiconductor (MOS) capacitors structured as Al/ZrGdO x /Si were prepared using an ultraviolet ozone (UVO)-assisted sol-gel method. The effects of heat treatment temperature on the microstructure, chemical bonding state, optical properties, surface morphology and electrical characteristics of the ZrGdO x composite films and MOS capacitors were systematically investigated. The crystalline phase of the ZrGdO x films appeared only at 600 °C, indicating that Gd doping effectively inhibits the crystallization of ZrO2 films. Meanwhile, as the heat treatment temperature increased from 300 °C to 600 °C, the content of oxygen vacancies decreased from 18.57% to 11.95%, and the content of metal-hydroxyl-oxygen bonds decreased from 14.72% to 8.64%. Heat treatment temperature proved to be effective in passivating the oxygen defects and reducing the trap density within the dielectric layer. At 500 °C, the MOS capacitor exhibited the best electrical characteristics, including the highest dielectric constant (k = 19.3), the smallest hysteresis (ΔV fb = 0.01 V), the lowest boundary trapping oxide charge density (N bt = 2.7 × 1010 cm-2), and the lowest leakage current density (J = 9.61 × 10-6 A cm-2). Therefore, adjusting the heat treatment temperature can significantly improve the performance of ZrGdO x composite films and capacitors, which is favorable for the application of CMOS devices in large-scale and high-performance electronic systems.

High-Performance Hydrogen Sensing at Room Temperature via Nb-Doped Titanium Oxide Thin Films Fabricated by Micro-Arc Oxidation.

Metal oxide semiconductor (MOS) hydrogen sensors offer advantages, such as high sensitivity and fast response, but their challenges remain in achieving low-cost fabrication and stable operation at room temperature. This study investigates Nb-doped TiO2 (NTO) thin films prepared via a one-step micro-arc oxidation (MAO) with the addition of Nb2O5 nanoparticles into the electrolyte for room-temperature hydrogen sensing. The characterization results revealed that the incorporation of Nb2O5 altered the film's morphology and phase composition, increasing the Nb content and forming a homogeneous composite thin film. Hydrogen sensing tests demonstrated that the NTO samples exhibited significantly improved sensitivity, selectivity, and stability compared to undoped TiO2. Among the fabricated samples, NTO thin film prepared at Nb2O5 concentration of 6 g/L (NTO-6) showed the best performance, with a broad detection range, excellent sensitivity, rapid response, and good specificity to hydrogen. A strong linear relationship between response values and hydrogen concentration (10-1000 ppm) highlights its potential for precise hydrogen detection. The enhanced hydrogen sensing mechanism of NTO thin films primarily stems from the influence of Nb2O5; nanoparticles doping in the anatase-phase TiO2 structure on the semiconductor surface depletion layer, as well as the improved charge transfer and additional adsorption sites provided by the Nb/Ti composite metal oxides, such as TiNb2O7 and Ti0.95Nb0.95O4. This study demonstrates the potential of MAO-fabricated Nb-doped TiO2 thin films as efficient and reliable hydrogen sensors operating at room temperature, offering a pathway for novel gas-sensing technologies to support clean energy applications.