Composite Films Research Articles

Cross-linked chitosan/H-ZSM-5 zeolite composite film for chromium removal from aqueous solutions: optimization using response surface methodology and adsorption mechanism assessment.

The present work investigates, for the first time, the synthesis of a composite film based on glutaraldehyde-cross-linked chitosan (GA-CS) and a natural zeolite (H-ZSM-5) and its application for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions under wide experimental conditions. The composite film (GA-CS-ZEO) characterization by using various analytical techniques confirms its successful production with promising physical, chemical, and thermal properties. The use of the response surface methodology (RSM) for the optimization of the Cr(VI) adsorption by this composite shows that that the maximum removal efficiency (82.39%) was achieved for a Cr(VI) concentration of 50mg L-1, an initial pH of 2.0, a contact time of 100min, and a temperature of 20°C. Moreover, the analysis of variance (ANOVA) and 3D graphs indicated that the pH and initial Cr(VI) concentration were the main factors that influence the Cr(VI) uptake efficiency. Besides that, the Cr(VI) removal by the GA-CS-ZEO was found to be spontaneous and endothermic and occurs mainly via physical mechanisms involving electrostatic interactions and hydrogen bonding. Regeneration study of the Cr(VI)-loaded composite showed that Cr(VI) can be rapidly and efficiently desorbed by 0.1M sulfuric acid. The results of the current research work highlight the important adsorption potential of Cr(VI) by the GA-CS-ZEO composite film and underscore its attractiveness and suitability for water treatment applications.

Understanding the impact of plasma functionalized MWCNTs on the structure, physicochemical and mechanical properties of PEMA

In this study, plasma functionalized multiwalled carbon nanotubes, f-MWCNTs, were incorporated into a poly(ethyl methacrylate), PEMA, polymer matrix at different wt.% (0.005, 0.01, and 0.02 wt.%) to prepare nanocomposite films using the traditional solution casting method. The XRD, Raman spectroscopy, XPS, TGA, mechanical analysis and UV–Vis spectroscopy techniques were employed to investigate the effects of the wt.% of f-MWCNTs on the structure, spectroscopic and other physiochemical properties of the synthesized films. XRD analysis showed a monotonic change in the PEMA structure upon incorporation of f-MWCNTs at different wt.%. The XPS results showed an increase of oxygen-based functional groups C-O and O-C-O on the PEMA/f-MWCNTs/ composite films compared to pure PEMA. Raman spectroscopy results consistent with the XRD and XPS findings, confirming the homogeneous distribution of f-MWCNTs in the PEMA matrix. Thermal stability of f-MWCNTs/PEMA improved as the f-MWCNTs content increased. Optical studies showed a reduction in the bandgap energy as the f-MWCNTs content increased, accompanied by significant improvements in optical properties such as refractive index (n), extinction coefficient (k), dielectric constants (ε′ and ε″), and optical conductivity (σopt). Mechanical testing revealed enhancements in breaking strength, Young’s modulus, yield stress, and elongation at break with increasing f-MWCNTs concentrations. Furthermore, the AC electrical conductivity of the films also improved, demonstrating better charge transport capabilities. These synergistic enhancements in optical, thermal, mechanical, and electrical properties make PEMA/f-MWCNTs nanocomposites promising candidates for advanced applications, including optoelectronic devices, optical components, and conductive packaging materials.

Microstructure and Properties of Ni3N Composite Films on Ni-Based Nanosheets by Magnetron Sputtering

Microstructure and Properties of Ni3N Composite Films on Ni-Based Nanosheets by Magnetron Sputtering

Triboelectric Nanogenerator-Based Flexible Acoustic Sensor for Speech Recognition.

The way people interact with machines through flexible acoustic sensors is revolutionizing the way we live. However, developing a human-machine interaction acoustic sensor that simultaneously offers low cost, high stability, high fidelity, and high sensitivity remains a significant challenge. In this study, a sensor based on a sound-driven triboelectric nanogenerator was proposed. A poly(vinylidene fluoride) (PVDF)/graphene oxide (GO) composite nanofiber film was obtained as the dielectric layer through electrospinning, and copper-nickel alloy conductive fabric was used as the electrode. An imitation embroidery shed structure was designed in the shape of a ring to secure the upper and lower electrodes and the dielectric layer as a whole. Due to the porosity of the electrode, the large contact area of the dielectric layer, and the high stability of the imitation embroidery shed structure, the sensor achieves a sensitivity of 4.76 V·Pa-1 and a frequency response range of 20-2000 Hz. A multilayer attention convolutional network (MLACN) was designed for speech recognition. The designed speech recognition system achieved a 99.5% accuracy rate in recognizing common word pronunciations. The integration of sound-driven triboelectric nanogenerator-based flexible acoustic sensors with deep learning techniques holds great promise in the field of human-machine interaction.

Interface engineering of 2D dielectric nanosheets for boosting energy storage performance of polyvinylidene fluoride-based nanocomposites with high charge-discharge efficiency.

Polyvinylidene fluoride (PVDF) film, with high energy density and excellent mechanical properties, has drawn attention as an energy storage device. However, conduction loss in PVDF under high electric fields hinders improvement in efficiency due to electrode-limited and bulk-limited conduction. Well-aligned multilayer interfaces of two-dimensional (2D) nanocoatings can block charge injection, reducing electrode-limited conduction loss in dielectric polymers. Thus, rational selection of 2D fillers is crucial for designing high-energy-density dielectric materials. This study explores 2D oxide nanosheets with varying dielectric constants and bandgaps, such as Ti0.87O2, Ca2Nb3O10, and montmorillonite (MMT). Ca2Nb3O10 nanosheets, with a higher dielectric constant and similar bandgap to Ti0.87O2, created a higher Schottky barrier (0.6 eV), resulting in a discharge energy density (Ud) of 26.4 J cm-3 at 720 MV m-1 in PVDF-Ca2Nb3O10 film. The PVDF-MMT film, coated with MMT nanosheets featuring a lower dielectric constant yet a higher bandgap, achieves a similar Ud of 26.8 J cm-3 at 720 MV m-1, with efficiencies (η) above 80% for both films. The results indicate that the bandgap and dielectric constant of 2D nanosheets play a crucial role in determining PVDF composites' energy storage density and efficiency, necessitating a balance between these parameters. Furthermore, ultraviolet (UV) irradiation was introduced to induce trap centers and inhibit charge conduction and energy loss in PVDF-based composites under high electric fields. Consequently, the UV-treated PVDF-MMT composite film achieves a Ud of 29.1 J cm-3 and an η of 78.3% at 750 MV m-1. This work offers an effective strategy for developing high-energy density, high-efficiency PVDF-based polymer materials.

Controllable Construction of Hollow Ni/NiO@PPy Particles for Broadband and Highly Efficient Microwave Absorption

AbstractMicrowave‐absorbing materials are widely used in electromagnetic protection and military stealth fields. Hollow structure materials, as efficient microwave absorbing materials, have garnered considerable attention, since they are beneficial to multiple reflection and enhance the attenuation loss of microwaves. Herein, a strategy is proposed to prepare hollow Ni/NiO@PPy particles using a water‐soluble template method combined with in situ polymerization process. The cuboid hollow Ni/NiO@PPy particles are constructed with Na2SO4 as templates and then filled into epoxy resin to form composite films with excellent microwave absorption properties. The Ni/NiO@PPy composite film under optimal conditions exhibits a minimum reflection loss value of −72.14 dB and the absorption rate is more than 99.99% with filling content of 10 wt.%. By adjusting the film thickness, an effective absorption bandwidth of 15.94 GHz can be achieved, which almost completely covers the S, C, X, and Ku bands. The CST simulation results confirm the outstanding radar cross‐section attenuation of the composite film. Remarkably, with an ultra‐low filling content of 2.5 wt.%, the composite film still achieves an absorption rate of 99.90%, demonstrating highly efficient microwave absorption with ultra‐low filling content.

Photofixation Pd Functionalization of ZnO Thin Films for Efficient Photocatalytic Removal of Doxycycline Antibiotic in Aqueous Phase

In this work, we demonstrate the co-catalytic modification of ZnO films via the photodeposition of palladium (Pd) to enhance the photocatalytic degradation of doxycycline (DC). Pristine ZnO films were synthesized using a sol–gel method and deposited onto glass substrates via dip-coating. The films were subsequently modified with Pd through chemical photodeposition under UV light, which facilitated the photoreduction of an aqueous 5 × 10−3 M Pd2+ precursor. The influence of varying UV photodeposition doses (2.5, 5, and 10 J/cm2) on the morphology and chemical composition of the Pd-modified films was investigated to control Pd surface coverage and chemical state. Characterization techniques included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). At low UV doses (2.5 J/cm2), approximately 1.6 at.% of Pd was photodeposited, primarily as PdO, while higher UV doses (5–10 J/cm2) increased the metallic Pd0 content. The photocatalytic degradation of DC was evaluated in both distilled and tap water, where Pd/ZnO films demonstrated significantly higher removal efficiency (40–380% higher) than pristine ZnO films, with those containing higher Pd0 levels exhibiting the greatest activity. Across all samples, removal efficiency in tap water was approximately double that in distilled water.

Incompatible Geometry Regulation of Nanowire Assemblies Enabled Light-Driven Shape Morphing and Motions.

Photoresponsive shape-changing materials have significant applications in miniaturized smart robotics and biomedicine powered in a remote and wireless manner. Existing light-fuelled soft materials suffer from limited continuous shape manipulation and constrained mobility and locomotive modes. One promising solution is developing a hierarchical structure design approach to integrate rapid, reversible photoactive molecular alignment and mechanically incompatible geometry in a macroscopic system. Here, a nanowire assemblies-induced geometry engineering method is reported for the fabrication of silver nanowire-incorporated nematic liquid crystalline elastomers with prominent anisotropic structures at multi-length scales and incompatible elasticity that show sharp morphological transitions among the rings, helicoids, and spirals with diverse helical configurations. The engineered composite films can realize complex light-driven motions including rotating, rolling, and jumping with the controlled directionality and magnitude that are pre-encoded in their both molecular and macroscopic configurations. Owing to the great controllability of multimodal locomotion, a spiral robot can undertake task-specific configuration to climb up complex terrains. The complete regulatory relationship among molecular orientation, shape geometry, and light-driven motions is also established. This study may open an avenue for elaborate design and precise fabrication of novel shape-morphing materials for future applications in intelligent robotic systems.

Rheological, microstructural, thermal and barrier properties of polylactide/polyethylene glycol/inulin/encapsulated cinnamon essential oil films

AbstractThe ongoing use of polymeric materials and associated pollution is a challenge to our society. It has resulted in a shift in the industry from polymeric to sustainable packaging. The aim of this work was to fabricate extruded polylactide (PLA)‐based packaging by incorporating inulin, polyethylene glycol, and cinnamon essential oil encapsulates. The fabricated film samples were characterized by various analytical tools (rheometer, TGA, FTIR, XRD, and AFM) to gain deeper insights into their compatibility and the effect of microstructure evolution on film‐forming properties for their potential packaging applications. Rheologically, the blend melt exhibited a shear‐thinning behavior and improved the mechanical rigidity of plasticized PLA films upon incorporation of CEO encapsulates. The thermal stability of the films was validated by the TGA thermograms, and the analyzed films showed insignificant variations from one another. The smoothness of the PLA/PEG/CEOINL film, along with the presence of some inulin particles on the surface, was evident. The XRD and FTIR peaks suggest a loss of volatiles during extrusion. The barrier properties of the films did not enhance with the addition of encapsulates or inulin to PLA. Overall, the PLA/PEG/CEOINL film has potential for active food packaging in anticipation of its antimicrobial properties, as demonstrated in the encapsulates.Highlights PLA/inulin/cinnamon essential oil active packaging films were fabricated. The addition of inulin lowered the mechanical and thermal properties of the film. The melt rheology of the films exhibited the shear‐thinning behavior. Unlike inulin, CEO distributes well on the PLA composite films.

Excellent Tribological Properties of WS2 Films in Air by Doping Copper

WS2 films exhibit excellent tribological properties in a vacuum, but they are prone to failure due to oxidation in air, which severely limits their application. Cu has great potential to improve the tribological properties of WS2, similar to that of Au and Ag. Thus, to clarify the contribution of Cu to the tribological properties of WS2 films and provide new insight for the development of new multi-environmentally adaptable films, this study deposited WS2-Cu composite films under different sputtering powers of the Cu target by magnetron sputtering systems, and the Cu target was supplied by DC power. Then, the structure of films was analyzed by FESEM, EDS and XPS. The results show that Cu is difficult to uniformly dope on the WS2 film at a high sputtering power of Cu target, showing possibly low solubility of Cu in WS2 film. However, a uniform and dense WS2-Cu composite film was deposited under the lower sputtering power of Cu target. Furthermore, the results of the nanoindentation test demonstrated that the WS2-Cu composite films exhibited high hardness (6.6 GPa). Finally, the tribological properties of the WS2-Cu films were examined, and their friction interface was characterized by SEM, EDS and TEM. The WS2-Cu film demonstrated superior tribological behavior in air (the average friction coefficient is 0.09), based on a special sliding interface, low oxidation levels of WS2 and Cu-rich transfer film. This study provides a new insight and a new method for improving the environmental adaptation ability of WS2 film.

Poly(vinyl alcohol) Nanocomposites Reinforced with CuO Nanoparticles Extracted by Ocimum sanctum: Evaluation of Wound-Healing Applications

This study focused on the synthesis of plant-mediated copper-oxide nanoparticles (OsCuONPs) via the sol–gel technique and the fabrication of OsCuONP-infused PVA composite films (POsCuONPs) utilizing the solvent casting method for wound-healing applications. The prepared OsCuONPs and nanocomposite films were characterized using UV–visible spectra, FTIR, SEM, XRD, TGA, water contact-angle (WCA) measurements, and a Universal testing machine (UTM) for mechanical property measurements. The UV and FTIR tests showed that OsCuONPs were formed and were present in the PVA composite film. Moreover, the mechanical study confirmed that there is an increase in the tensile strength (TS) and Young’s modulus (Ym) with 21.75 MPa to 32.50 MPa for TS and 24.80 MPa to 1128.36 MPa for Ym, and a decrease in the % elongation at break (Eb) (394.32 to 75.6). The TGA and WCA study results demonstrated that PVA films containing OsCuONPs are more stable when subjected to high temperatures and demonstrate a decreased hydrophilicity (60.89° to 89.62°). The cytotoxicity and hemolysis tests showed that the CuONPs-3 containing composite films (PVA/OsCuONPs with a wt. ratio of 1.94/0.06) are safe to use, have a good level of cell viability, and do not break down blood. This is true even at high concentrations. The study also discovered that cells moved considerably in 12 and 24 h (13.12 to 19.26 for OsCuONPs and 312.53 to 20.60 for POsCuONPs), suggesting that 60% of the gaps were filled. Therefore, the fabricated POsCuONP nanocomposites may serve as a promising option for applications in wound healing.

Use of Syzygium cumini biomass as reinforcing filler in polyvinyl chloride and their antibacterial and biodegradation properties

AbstractThis study explores the utilization of lignocellulosic biomass derived from Syzygium cumini seeds (S. Cumini) as an eco‐friendly reinforcing filler for polyvinyl chloride (PVC) composites. The need for sustainable and biodegradable materials in polymer applications motivated this work, particularly to address environmental concerns associated with conventional PVC. Composite films with varying concentrations of S. Cumini seed filler were prepared using solution casting technique. The structural integrity and interactions within the composites were confirmed through X‐ray diffraction (XRD) and Fourier‐transform infrared (FTIR) spectroscopy. The SEM analysis showed an average particle size of 6–14 μm and also revealed the modifications in morphology upon filler addition. Biodegradability was assessed using hydrolytic degradation and soil‐burial tests, indicating enhanced environmental compatibility compared to pure PVC. The hydrophilicity of the composites improved, as indicated by an increasing in the water contact angle from 79.4° (hydrophilic) to 107° (hydrophobic). Suppressed S. aureus activity of the PVC composite film has shown its antimicrobial behavior. These properties suggest that S. Cumini – reinforced PVC composites can serve as promising materials for polymer‐based medical devices, offering enhanced resistance to bacterial contamination while addressing sustainability challenges.Highlights Lignocellulosic biomass S. Cumini was used as reinforcing filler in PVC films. S. Cumini extract improved the antimicrobial properties of the films. Hydrolytic dehydration and soil‐burial tests showed enhanced biodegradability. Hydrophilicity increased, as evidenced by a rise in the water contact angle. Better bacterial resistance enhances the use in polymer‐based medical devices.

Reinforcement of Biodegradable PLA-PVA Composite Films with Carbon Nanotubes: Mechanical and Thermal Property Analysis

Reinforcement of Biodegradable PLA-PVA Composite Films with Carbon Nanotubes: Mechanical and Thermal Property Analysis

Nanochitin From Crab Shells: Production, Chemical Modification, Composite Materials, and Physiological Functions.

Large quantities of crab shells are generated in food-processing plants. In this review, the authors summarize a series of research findings on the production of nanochitin, its physical properties, chemical modifications, and functions, which have not been fully addressed in existing literature. Nanochitin, which has a width of 10nm, is derived from chitin, the main component of crab shells, using a technology similar to that used to produce nanocellulose from wood. Unlike conventional chitin, nanochitin is well dispersed in water, making it easy to mold and process into various products for different applications. They can also be modified for specific uses through processes such as acylation and etherification to enhance their physical properties and add functionality. Nanochitin, which are known for their exceptional mechanical strength, can be blended with resins to create composite films with improved strength and elasticity. These films maintain the transparency of the resin, reduce its thermal expansion, and offer reinforcement. Chitin and its derivative chitosan are used as wound dressings, hemostatic agents, and health foods. Nanochitin and its deacetyl derivatives have diverse functions such as topical medicine for the skin, ingestion as a health food, and use as pesticides or fertilizers for plants.

Wearable Body Temperature Sensing with Autonomous Self‐regulated Joule Heating and Passive Cooling for Healthcare Applications

AbstractThe positive temperature coefficient (PTC) effect observed in conductive polymer composites (CPCs) holds significant promise due to its wide materials selection and ability to offer enhanced sensitivity. However, traditional CPCs have relatively high PTC switching temperatures (typically above 100 °C) and are often unsuitable for bodily healthcare devices. This study introduces a novel approach leveraging the synergistic effect of an eco‐friendly fatty acid, namely lauric acid (LA), with flexible styrene‐ethylene‐butylene‐styrene (SEBS) thermoplastic elastomer (TPE) as a matrix and graphene nanoplatelets (GNPs) as a conductive filler. The composite film demonstrates exceptional temperature responsiveness at body‐relevant temperatures (35–40 °C) with a PTC intensity reaching an unprecedented 4 orders of magnitude, set apart by its fine‐tuning ability across a remarkable detecting temperature interval (Maximum temperature coefficient of resistance (TCR): 471.4% °C−1). This advancement is facilitated through a carefully engineered morphology, wherein the distribution of LA significantly influences the conductive network's reformation within the composite, with the in‐situ optical microscope used to reveal the reformation of the conductive network structure. The flexible composite demonstrates significant potential for body temperature sensing, self‐regulating heating, and passive cooling, paving the way for future developments in eco‐friendly, highly sensitive, and flexible sensors in wearable health monitoring and thermotherapy.

Fabrication of ethylcellulose/technical alkaline lignin composite film with high anticorrosion performance in NaCl, HCl, and KOH solutions.

Technical alkaline lignin (TAL)-based composite films have been developed for anti-corrosion applications, during which one-component solvents, including acetone and ethanol, were employed. The poor solubility of TAL in the abovementioned solvents undoubtedly resulted in inhomogeneous surface micromorphology and the consequent unstable performance. The present study provides a series of ethylcellulose/TAL (EC/TAL) composite films with uniform surface microstructure by using the 1,4-dioxane/water binary solvent. EC/TAL film presents an excellent tensile stress of 26.4MPa with an elongation at break of 26.8%, which is better than those of EC film (18.4MPa and 13.3%). The addition of TAL significantly improves the thermostability of the composite films. The lignin component also contributes to the corrosion inhibition performances. In the 1mol/L HCl electrolyte, the corrosion inhibition efficiency achieves 98.8%, and these performances are all higher than 90% in 3.5wt% NaCl and 0.1mol/L KOH solutions. All these results manifest that the 1,4-dioxane/water binary solvent can be used to form TAL-containing films. The performances of as-prepared films indicate their excellent potential as an anti-corrosion coating.

Enhancing fruit preservation with sodium alginate films incorporating propolis extract and graphene oxide.

In this work, sodium alginate (SA) composite films containing propolis extract (PRO) and graphene oxide (GO) were developed. Subsequently, the effects of PRO and GO on different properties of SA composite films were studied, and the films were characterized by scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The PRO release properties and fruit preservation performance of the developed composite films were also investigated. The results showed that the incorporation of PRO resulted in a 51.16% increase in tensile strength. The simultaneous incorporation of PRO and GO reduced water vapor permeability (WVP) by 22.56% compared to the SA film. The temperatures at which the SA/GO/PRO film lost 5% of its weight were 8.0°C higher than those of the SA film. The incorporation of GO into the SA/PRO composite film also modulates the release of PRO. Furthermore, the incorporation of PRO and GO improved the tensile strength of the SA film, as reflected in the microstructure of the films. The reduced WVP of the SA composite film allowed the packaged blueberries to exhibit less weight loss and shrinkage, thereby prolonging their shelf life.

Effect of strengthening agents on properties of dual-modified cassava starch-based degradable films.

Insufficient hydrophobicity and mechanical properties pose significant challenges in the development of starch-based degradable films. This study prepared modified (crosslinked, acetylated, and crosslinked & acetylated) cassava starch films, and different concentrations of strengthening agents (polyvinyl alcohol, sodium alginate, gelatin, and hyaluronic acid) were added to produce modified starch composite films. The physical properties, structure characteristics, and degradability of these films were systematically evaluated. The dual-modified (crosslinked & acetylated) starch film exhibited superior hydrophobic properties (contact angle=90.04°), and the addition of strengthening agents significantly enhanced the tensile strength of the composite films (p<0.05). Fourier transform infrared spectra confirmed that the strengthening agents interacted with starch through hydrogen bonding. Additionally, the hyaluronic acid-starch composite film exhibited the most rapid degradation in soil (53% weight loss after 30days of storage) and achieved the highest comprehensive score for physical properties. This film combined exceptional hydrophobicity and mechanical properties, making it an ideal candidate for food packaging applications. These findings suggest that the hyaluronic acid-starch composite film has broad potential applications in the field of degradable food packaging films.

Nanometer thick iron garnet films with high Faraday rotation

Here we demonstrate nanometer thick iron garnet films with high specific Faraday rotation suitable for the magneto-optical applications. Bismuth-substituted iron garnet films of compositions Bi1Y2Fe5O12 and Bi1Tm2Fe5O12 deposited on gadolinium gallium garnet substrate are fabricated and characterized. Their thicknesses range from 2 to 10 nm, which corresponds to just a few crystal lattice constants. Spectacularly, Faraday rotation of the 2 nm thick Bi1Y2Fe5O12 film reaches 29.3deg/µm at 420 nm that is comparable to the single crystal micrometer thick films of similar composition. The film surface morphology by atomic force microscopy gives root mean square (RMS) roughness of the nanometer thick films as small as 0.13 nm that is also similar to the RMS of single crystal micrometer thick films. Moreover, the 3 nm thick Bi1Tm2Fe5O12 films demonstrate a pronounced effective uniaxial anisotropy. These all make the fabricated nanometer thick films very promising for their potential applications in magneto-optical devices and quantum technologies.

Based on electrostatic adsorption constructing neural network-like structure of BNNS-OH@CNF composite films with excellent thermal management and electrical insulation performance

Based on electrostatic adsorption constructing neural network-like structure of BNNS-OH@CNF composite films with excellent thermal management and electrical insulation performance