Composite Films Research Articles

Experimental Study of the Interaction of Silica Nanoparticles with a Phospholipid Membrane

This study aims to contribute to the physical understanding of the behavior of nanoparticles in lipid–nanoparticle composite systems. Therefore, composite films were formed on hydrophilic or hydrophobic surfaces through the sequential adsorption of liposomes and silica nanoparticles. The process was performed using dispersions with different pHs by using optical fixed-angle reflectometry. In the first step, liposomes were deposited on the surface, resulting in a lipid monolayer or bilayer depending on the surface’s properties. The kinetic experiments indicated that the adsorption of liposomes is a diffusion-limited process that depends on the pH and the properties of the substrate. In the second step, negatively charged nanoparticles were adsorbed on the membrane as a result of the electrostatic interactions with the positively charged domains on the membrane. The amounts of liposomes and particles adsorbed depend on the charge density of the particles and net charge density of the membrane: an increase in the pH and hydrophobicity of the surface leads to a decrease in the amounts adsorbed because of the increase in the electrostatic repulsion between particles and lipids. The procedure was supplemented with the formation of two liposomes/nanoparticles bilayers.

Temperature Dependence on Microstructure, Crystallization Orientation, and Piezoelectric Properties of ZnO Films.

This study has investigated the effects of different annealing temperatures on the microstructure, chemical composition, phase structure, and piezoelectric properties of ZnO films. The analysis focuses on how annealing temperature influences the oxygen content and the preferred c-axis (002) orientation of the films. It was found that annealing significantly increases the grain size and optimizes the columnar crystal structure, though excessive high-temperature annealing leads to structural degradation. This behavior is likely related to changes in oxygen content at different annealing temperatures. High resolution transmission electron microscopy (HR-TEM) reveals that the films exhibit high-resolution lattice stripes, confirming their high crystallinity. Although the films exhibit growth in multiple orientations, the c-axis (002) orientation remains the predominant crystallographic growth. Further piezoelectric property analysis demonstrates that the ZnO films annealed at 400 °C exhibit enhanced piezoelectric performance and stable linear piezoelectric behavior. These findings offer valuable support for optimizing the piezoelectric properties of ZnO films and their applications in piezoelectric sensors.

Insight Into the Film‐Forming Properties of Pea Protein Isolate Improved by Cellulose Nanocrystals From the Perspective of Water Phase Stabilization

ABSTRACTThis study is dedicated to explore the effect of cellulose nanocrystal (CNC) on the film formability of pea protein isolate (PPI) and propose the regulation mechanism from the perspective of water phase stabilization. Compared with PPI film, the CNC‐PPI composite films showed the improvement in mechanical properties and barrier properties of water/air. CNC reduced the proportion of free water in the PPI film and induced its conversion to immobilized water. From the microscopic observation of the films, it could be found that 0.25%–0.75% CNC made the dispersion of PPI more uniform, and formed more compact film structure. Meanwhile, the exposure of tyrosine and tryptophan in PPI molecules and the increase in the content of β‐sheet resulted in the improvement of film‐forming properties of PPI. The enhanced stability of water phase induced by CNC restrained the formation of water channels, thus improving the structural integrity of gel network and the film‐forming properties of PPI. This work provided a theoretical reference for regulation of the film‐forming properties of PPI with CNC, which was expected to improve the product performance of PPI films and enrich the application scenarios of PPI.

Application of lanthanum-modified silk fibroin/polyvinyl alcohol film for highly selective defluoridation in brick tea infusion.

To mitigate the risk associated with water-soluble fluoride in tea and to have less influence on the contents of tea infusion, a highly selective lanthanum modified silk fibroin (SF) and polyvinyl alcohol (PVA) composite film (SF/PVA-La) was prepared to remove fluoride from brick tea infusion. Notably, SF/PVA-La could remove about 48% of the fluoride from in brick tea infusion within 30min. Importantly, the reduction in total tea polyphenols in brick tea did not exceed 10%, and the reduction in caffeine was only 0.4%. In addition, the Langmuir model revealed a maximum fluoride adsorption capacity of 9.15mg/g for SF/PVA-La in brick tea infusion. Both FTIR and XPS analyses confirmed that SF/PVA-La engages in electrostatic adsorption of fluoride ions, with ion exchange occurring between the hydroxyl groups on its surface and the fluoride ions. These findings underscore the potential of SF/PVA-La as an effective material for selective fluoride removal from brick tea infusions.

Fabrication of self-reinforced chitin composites by double crystalline blend approach

In this study, all-chitin composite films, named self-rein orced chitin composite (SR-ChC) films, were fabricated from aqueous acetic acid dispersions of highly-crystalline scaled-down chitin nanofibers (SD-ChNFs, crystalline index (CI) = 90.5 %) and scaled-down low-crystalline chitin (SD-LC-Ch, CI =57.4 %) powder. A SD-ChNF dispersion with aqueous acetic acid was obtained by regeneration from a chitin ion gel and subsequent disintegration of the resulting ChNFs. Separately, the SD-LC-Ch powder was prepared by treating chitin powder under alkaline conditions and subsequent additional deacetylation, which showed well-dispersibility in aqueous acetic acid. The two dispersions were mixed, followed by suction filtration and drying, to obtain the SR-ChC films. The composite films were characterized by scanning electron microscopic, powder X-ray diffraction, and tensile testing measurements. As weight ratios of the SD-LC-Chs increased, the components gradually embedded the SD-ChNFs, allowing reduction of the crystallinity of the SR-ChC films (CIs = ~ 63.4 %). The tensile testing revealed that the SR-ChC film with the SD-LC-Ch/SD-ChNF weight ratio of 6.6/1 exhibited superior mechanical properties, including tensile strength of 64.0 MPa, elongation of 22.4 % at break, Young's modulus of 0.924 GPa, and toughness of 1109 J m−3. The mechanism for the improvement of properties was also discussed.

Multi-performance sodium alginate-based composite films for sensing and electromagnetic shielding.

As science and technology progress swiftly, the demand for high-performance composite films designed to shield against electromagnetic interference (EMI) and for strain sensing applications has significantly increased, making these films essential components for the future generation of smart wearable electronics. However, designing and developing multifunctional flexible composite films remains a considerable challenge. This study employed vacuum-assisted filtration techniques combined with calcium ion cross-linking to create multifunctional MXene/sodium alginate/liquid metal (MSL) composite films exhibiting exceptional EMI shielding and strain sensing capabilities. The mechanical strength of the MSL composite films was optimized by implementing continuous hydrogen bonding and ionic interactions among MXene, sodium alginate, liquid metal (LM), and calcium ions, resulting in a tensile strength of 71.71 MPa. The composite film exhibits excellent electromagnetic absorption properties, resulting in an exceptional EMI shielding efficacy of 50.61 dB and a specific shielding effectiveness value of 7563 dB·cm2·g-1. This is due to the heterogeneous interface between MXene and LM nanoparticles. Furthermore, the composite film exhibits favorable electrothermal and photothermal conversion capabilities. The film can be a flexible sensor to detect human motion, contingent on the conductive network between MXene and LM. This research illustrates the potential of multifunctional MSL composite films for EMI shielding and human motion monitoring, offering a promising pathway for creating adaptable wearable electronics in challenging electromagnetic conditions.

Hierarchical configuration design of PAN/Gr@MWCNTs composite film with superior electromagnetic shielding and excellent Joule heating via in-situ sedimentation strategy

With the rapid development of 5G communication technology, the surge in the number of antenna modules for intelligent terminal equipment has led to the intensification of electromagnetic radiation and interference problems, posing a major threat to electronic equipment safety, information systems stability, and human health. Traditional electromagnetic shielding materials have made it difficult to meet the demand for intelligent, integrated electronics. In this study, we proposed an in-situ sedimentation strategy to fabricate flexible polyacrylonitrile/graphene@multi-walled carbon nanotubes (PAN/Gr@MWCNTs) composite film with hierarchical double-layered structures, thus realizing ultra-thin, highly conductive, and excellent electromagnetic shielding and Joule heating properties. Particularly, the as-formed hierarchical film possessed an ultra-thin thickness of 0.158 mm and a high conductivity of 1660.26 S/m, simultaneously accompanied by an electromagnetic interference shielding efficiency (EMI SE) of 42.82 dB and a specific shielding efficiency (SSE) of 271.01 dB/mm. In addition, the film exhibited excellent Joule heating capability in the voltage range of 1.50-2.25 V. This study provides innovative ideas for developing flexible electromagnetic shielding films, which are of great scientific significance and potential application in electromagnetic radiation protection.

Recyclable PVA/starch/Ti3C2Tx MXene nanocomposite films with superior mechanical and barrier properties.

The fabrication of eco-friendly and high-performance composite materials has gained significant attention for multifunctional applications. Polyvinyl alcohol (PVA)/starch composite films containing varying amounts of Ti3C2Tx MXene (2.5-10wt%) were produced using a simple casting method. The impact of MXene nanoplatelets on the films' chemical structure and physical properties were thoroughly analysed. It was revealed that MXene formed hydrogen bonding with the polymer matrix and tended to align in the plane of the films. The mechanical properties of the PVA/starch blend were significantly improved with increasing MXene loading. With 10wt% MXene, the Young's modulus (YM) and tensile strength (TS) increased by 669% (from 255.7 to 1965.3MPa) and 292% (from 9.2 to 36.1MPa), respectively. Additionally, the presence of MXene greatly improved the films' water and oxygen barrier properties, reducing water vapor permeability (WVP) by 91% and oxygen permeability (OP) by 79%. These improvements are attributed to the homogeneous dispersion of MXene within the blend and the interfacial interactions between the components. Furthermore, the PVA/starch/MXene composite films exhibited excellent recyclability, maintaining their mechanical and barrier properties even after recycling, demonstrating their potential for repeated use without performance loss. Overall, the developed composite films present a promising sustainable solution for applications in materials requiring advanced mechanical and barrier performance.

Optimization of PVA/ alkali treated ramie fiber-based composite film for green packaging application using response surface methodology approach

Natural fiber-reinforced composites have gained significant attention as eco-friendly alternatives in sustainable packaging due to their biodegradability, renewability, and low environmental impact. This study aimed to produce an optimum composite film by combining PVA with alkali-treated-ramie fiber using a central composite design (CCD). This research investigates the effects of two independent factors, PVA (60-100 wt%) and alkali-treated ramie fiber (0-40 wt%), on three dependent variables: tensile strength, elongation at break (%), and contact angle of the composite film. Response surface methodology (RSM) determined that the optimal film composition for packaging application is 80 wt% PVA and 20 wt% alkali treated-ramie fiber. This combination resulted in a tensile strength of 46.03 MPa, an elongation limit of 251.4 %, and a contact angle of 66.75°. The film, which was produced utilizing the optimal outcomes, was then subjected to several characterization methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, contact angle measurement, water vapor transmission rate analysis, and FTIR spectroscopy. This outcome exemplified the optimal use of processed Ramie fiber in a polymer matrix for the purpose of eco-friendly packaging.

Preparation, characterization, and antibacterial application of cross-linked nanoparticles composite films

This study aimed to prepare a composite film by blending cross-linked tapioca starch (CLTS) with sodium alginate (SA), silver nanoparticles (AgNPs), and ZnO nanoparticles (ZnOs). The effects of SA, AgNPs, and ZnOs at different concentrations (1–3 wt%) on the mechanical properties, optical properties, thermal stability, and antibacterial activity of cross-linked starch films were also investigated. The structures of the films were examined by Fourier transform infrared spectroscopy and X-ray diffraction. The results showed that the cross-linked starch, SA, AgNPs, and ZnOs had good biocompatibility and interactions, and the AgNPs and ZnOs had synergistic effects. ESEM also revealed that the polymer and nanofiller had good compatibility. The Young's modulus and tensile strength values of the CLTS/SA/AgNP/ZnO film increased from 351.64 MPa to 1879 MPa and from 13.77 MPa to 53.76 MPa, respectively, with increasing concentration of nano-ZnO particles. The decrease in elongation at break from 48.15 % to 24.60 % indicated a certain increase in rigidity and a decrease in flexibility. The ultraviolet barrier and thermal stability of the CLTS/SA/AgNP/ZnO film effectively improved, and the antibacterial activity increased; the antibacterial effect of the CLTS/SA/AgNP/ZnO film was better than that of Streptococcus aureus. The study revealed that the CLTS/SA/AgNP/ZnO composite film represented a packaging material with superior performance.

Patternable chiral Au nanocrystal-doped composite films for information encryption: the role of optical rotation.

Optical information encryption technology has garnered significant attention in currency security, information protection, and personal identification. While optical metasurfaces are considered ideal platforms for information encryption, their high cost and time-intensive fabrication processes have limited their widespread applications. To address this, emergent chiroptical nanomaterials offer new opportunities for information encryption through their polarization capabilities. In this study, composite films consisting of chiral Au nanocrystals embedded in curable polymers are utilized as a patternable platform for information encryption. Theoretical simulations demonstrate that chiral Au nanocrystals can rotate linearly polarized light of different wavelengths in various directions. Notably, Au nanocrystals with opposite chirality show reversed optical rotation effects for linearly polarized light while exhibiting the same extinction properties for non-polarized light. Based on these investigations, patternable composite films with embedded chiral Au nanocrystals are fabricated, showcasing their potential to encode information via optical rotation. This work establishes the feasibility of chiral Au nanocrystals as a patternable platform for information encryption and presents a simple, convenient, and cost-effective approach for optical information security.

Momentous Roles of Ag nanoparticles in enhancing CO2 photoreduction activity of Z-scheme heterojunction Ag/Bi12SiO20/BiOBr composite film

Momentous Roles of Ag nanoparticles in enhancing CO2 photoreduction activity of Z-scheme heterojunction Ag/Bi12SiO20/BiOBr composite film

Enhanced functionalities in flexible poly (vinylidene fluoride-trifluoroethylene)/cerium oxide doped sodium bismuth titanate [P(VDF-TrFE)/NBT-CeO2] ceramic polymer composite films: A comprehensive investigation of piezoelectric, pyroelectric, and ferroelectric properties

In the pursuit of innovative smart polymer piezoelectric ceramic composites, we present a thorough examination of the physical, structural, and polarization characteristics of a novel flexible polymer ceramic composite comprising sodium-bismuth titanate (NBT) doped with 0.6 mass % CeO2 as ceramic fillers embedded in a poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) polymer matrix. The incorporation of these fillers serves to increase both the mechanical strength and functional attributes of the resulting polymer-ceramic composites. Various volume percentages of ceramic fillers were employed, and the experimental effective dielectric permittivity results were systematically fitted to established theoretical models, including Maxwell, Clausius−Mossotti, Furukawa, and effective medium theory (EMT). Our findings reveal that the composite films exhibit exceptional piezo-, pyro-, and ferroelectric properties when compared to the pristine P(VDF-TrFE) copolymer. The optimum concentration of NBT-0.6 CeO2 filler was determined to be 0.2 vol fraction resulting in a remarkable enhancement of the key parameters. Specifically, the pyroelectric coefficient increased from 32 μC/m2K to 43 μC/m2K (a ∼35 % increment), remnant polarization surged from 80 mC/m2 to 166 mC/m2 (an impressive ∼110 % increment), and the piezoelectric constant (d33) elevated from −38 pC/N to 49 pC/N (a substantial ∼30 % increment). These findings signify the potential of these optimized samples for applications in high energy density capacitors and/or highly integrated and intelligent piezoelectric devices. This comprehensive investigation not only advances our understanding of the synergistic effects within polymer-ceramic composites but also underscores the potential of the proposed material system for practical applications, providing valuable insights for the development of advanced multifunctional materials.

Research on high thermal conductivity PPENK/PVP modified BN electrospinning hot-pressed multifunctional nanocomposite films

Design and construction of PPENK/MBN composite films with ‘wafer biscuits’ structure.

Gold nanoparticle-modified single-walled carbon nanotube terahertz metasurface for ultrasensitive sensing of trace proteins.

Research on metasurface sensors with high sensitivity, strong specificity, good biocompatibility and strong integration is the key to promote the application of terahertz waves in the field of biomedical detection. However, traditional metallic terahertz metasurfaces have shortcomings such as poor biocompatibility and large ohmic loss in the terahertz frequency band, impeding their further application and integration in the field of biosensing detection. Here, we overcome this challenge by proposing a high-performance terahertz metasurface based on gold nanoparticles and single-walled carbon nanotubes composite film. Compared with metal materials, carbon nanotubes not only have better biocompatibility, which can reduce the potential adverse reactions between metasurfaces and biological samples, but also have strong tunability in electrical and optical properties. Experimentally, we reveal a method to adjust the dielectric properties of single-walled carbon nanotube films by doping with gold nanoparticles. Leveraging this mechanism, we designed and prepared a single-walled carbon nanotube terahertz metasurface composed of periodically arranged asymmetric open resonant rings. Compared with pure single-walled carbon nanotube films, this device based on a composite single-walled carbon nanotube films have better localized electromagnetic field enhancement characteristics. Through integration with microfluidic channels, this metasurface sensor can achieve direct detection of SAA proteins in solution environments at the fM level. In addition, the device also exhibits a detection sensitivity of 41GHz/fM. This work has not only made significant progress in the design and function of new high-sensitivity carbon-based terahertz metasurfaces, but also laid the foundation for its application in liquid environment detection of trace biological samples.

Adhesive silk fibroin/magnesium composite films and their application for removable wound dressing.

Silk fibroin is a naturally abundant biomaterial renowned for its excellent biocompatibility and biodegradability, making it a promising candidate for biomedical applications like wound dressings. However, traditional silk fibroin materials often lack sufficient mechanical strength, adhesion, and the ability to modulate inflammation and oxidative stress-factors crucial for effective wound healing. To address these limitations, regenerated silk fibroin/magnesium ion [RSF/Mg(II)] composite films were developed by incorporating Mg(II) ions into RSF solutions. These films were characterized using Raman spectroscopy, mechanical testing, and biocompatibility assessments, and their wound-healing efficacy was evaluated in a mouse skin defect model. The RSF/Mg(II) composite films exhibited superior adhesion, higher transparency, and enhanced mechanical flexibility compared to pristine RSF films. They also demonstrated anti-inflammatory and antioxidative properties, effectively reducing cell apoptosis and reactive oxygen species levels in vitro. In vivo, the RSF/Mg Mg(II) composite films significantly accelerated wound healing in mice, improving epidermal thickness, collagen deposition, and promoting blood vessel formation. This study highlights the potential of RSF/Mg(II) composite films as advanced wound dressings with improved biocompatibility and biological activity, offering valuable insights for the development of Mg(II) ion-based biomaterials in wound healing and tissue regeneration applications.

Electrophoretically deposited artificial cathode electrolyte interphase for improved performance of NMC622 at high voltage operation

A composite film, composed of Li6PS5Cl ion-conducting nanoparticles and a polymerized ionic liquid binder, was electrophoretically deposited onto the LiNi0.6Mn0.2Co0.2O2 cathode surface, forming an artificial cathode electrolyte interphase.

Synergistic color-changing and conductive photonic cellulose nanocrystal patches for sweat sensing with biodegradability and biocompatibility.

Given the ongoing requirements for versatility, sustainability, and biocompatibility in wearable applications, cellulose nanocrystal (CNC) photonic materials emerge as excellent candidates for multi-responsive wearable devices due to their tunable structural color, strong electron-donating capacity, and renewable nature. Nonetheless, most CNC-derived materials struggle to incorporate color-changing and electrical sensing into one system since the self-assembly of CNCs is incompatible with conventional conductive mediums. Here we report the design of a conductive photonic patch through constructing a CNC/polyvinyl alcohol hydrogel modulated by phytic acid (PA). The introduction of PA significantly enhances the hydrogen bonding interaction, resulting in the composite film with impressive flexibility (1.4 MJ m-3) and progressive color changes from blue, green, yellow, to ultimately red upon sweat wetting. Interestingly, this system simultaneously demonstrates selective and sensitive electrical sensing functions, as well as satisfactory biocompatibility, biodegradability, and breathability. Importantly, a proof-of-concept demonstration of a skin-adhesive patch is presented, where the optical and electrical dual-signal sweat sensing allows for intuitive visual and multimode electric localization of sweat accumulation during physical exercises. This innovative interactive strategy for monitoring human metabolites could offer a fresh perspective into the design of wearable health-sensing devices, while greatly expanding the applications of CNC-based photonic materials in medicine-related fields.

In-vitro investigation of chitosan/polyvinyl alcohol/TiO2 composite membranes for wound regeneration

Bacterial infections significantly delay the physiological wound healing process and can cause further damage to the wound region. In the current work, we aim to design titanium dioxide nanoparticles (TiO2 NPs) incorporated with chitosan (Chi) and poly(vinyl alcohol) (PVA) film using the casting method and to study their potential for faster wound healing. The prepared TiO2 NPs were analyzed for physicochemical properties, and TEM results showed an average particle size of 39.6nm. The nanocomposite films were scrutinized by FTIR, XRD, and TGA analyses. The effective incorporation of the nanoparticles and their uniform dispersion within the Chi/PVA matrix was confirmed through SEM analysis. The composite films exhibited excellent hydrophilic properties (64.3º), along with favorable swelling and degradation rates, and mechanical properties similar to native skin tissue, ensuring comfortable interaction with wound beds. The better hemocompatibility, with an erythrocyte lysis percentage of 3.52%, further supports the wound healing properties of these films. Additionally, composite films possess excellent antibacterial activity against wound pathogens such as B. subtilis and E.coli. Furthermore, an in vitro wound closure rate of 92.3% at 48 hours was observed for the TiO2 incorporated film (CPT3) using fibroblast HIH3T3 cells. The results suggest that it could be a promising biomaterial for wound healing application.

Transparent cellulose-lignin films containing Fe3+ with high UV absorption for thermal management.

In this paper, cellulose-lignin films containing Fe3+ were prepared by the codissolution-precipitation method, and the films have high transparency as well as high UV absorption. In this process, kraft lignin chelates with Fe3+ and then bonds with cellulose through hydrogen bonding, evenly distributing within the film. The morphological results showed that the kraft lignin chelated with Fe3+ bound tightly linked to cellulose within the Fe@cellulose-lignin composite films. The addition of Fe3+ made the composite film (C-Fe-0.7-L) maintain a high transmittance of 66.9% at 600nm with excellent UV absorption. Excellent UV absorption performance, completely shielded from both Ultraviolet A (UVA), Ultraviolet B (UVB), and Ultraviolet C (UVC), and improved the thermal stability of the film. Under 100mWcm-2 solar irradiation, the temperature of C-Fe-0.7-L rose rapidly to 60.7°C. Based on this property, solar energy is transformed into kinetic energy, which realizes the photothermal conversion of solar energy. This work realizes the use of transparent films for energy utilization.