Nanofiber Films Research Articles

Effect of Glycerol and Sisal Nanofiber Content on the Tensile Properties of Corn Starch/Sisal Nanofiber Films.

Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry.

Effect of Electrospun Nanofibrous Film on Drilling-Force Reduction for Fine-Hole Drilling in Metals

Effect of Electrospun Nanofibrous Film on Drilling-Force Reduction for Fine-Hole Drilling in Metals

Harnessing microscopically opposite wettability in Janus nanofiber film for solar steam generation and photodegradation

Amphiphilic Janus nanofibers film composed of microscopically assembled hydrophilic and hydrophobic nanofibers is fabricated as a base film for the solar steam generator possessing functions of solar steam generation and photodegradation. The amphiphilic Janus nanofibers film integrates many advantageous properties including water pumping, thermal resisting, self floating, salt resisting, and high stability, which make it an excellent base film for solar steam generators. The mixture comprising carbon nanotubes, black TiO2 nanoparticles and poly(dopamine) is synthesized as a dual-functional photothermal layer on the solar steam generator for realizing photothermal conversion and photocatalysis. The fabricated solar steam generator can achieve a superior water evaporation rate (2.491 kg m−2 h−1, 1 sun) and synchronously degrade organic pollutants. Furthermore, it is delighted to find that the water evaporation rate can be boosted while treating organic-contaminated water. The synergistic property of solar steam generation and photodegradation offers an inspiration in the fields of wastewater elimination and clean water generation.

Multifunctional pectin and lignin-containing cellulose nanofiber films with improved UV resistance and mechanical properties

This study aimed to study the real-time interaction of apple pectin and LCNF using Quartz crystal microbalance with dissipation monitoring (QCM-D) to understand the compositional factors that influence their film formation and assess the impact of varying polymer ratios (0–100%) on the UV resistance, hydrophobicity, and mechanical properties of resulting composite films. Results revealed that apple pectin forms partially irreversible interaction with LCNF, evidenced by a frequency change of 14.9 Hz after the final rinsing stage. This finding was supported by FTIR of the composite films, demonstrated by a shift of the broader –OH stretching vibration at 3325 cm−1 to 3302 cm−1 due to the formation of strong hydrogen bonding. LCNF-based films (LCNF >50%) were less soluble in water compared to pectin-based films (pectin >50%) due to less permeable structure and hydrophobic lignin which interferes in hydrogen bonding with water. Pectin-based films displayed high transparency (%Transmittance >89% at 650 nm) and lower hydrophobicity. Due to the presence of lignin chromophores, the UV shielding property was the highest for LCNF-based films as it almost completely shielded the UV spectrum (%T ∼0 at 320 nm). The reinforcement provided by LCNF significantly enhanced the mechanical properties of the films. Consequently, this study offers valuable insights into the real-time interaction dynamics between apple pectin and LCNF, facilitating the development of biocomposite films with versatile properties that hold significant promise for a wide range of applications.

Air-Assisted Electrospinning of Dihydromyricetin-Loaded Dextran/Zein/Xylose Nanofibers and Effects of the Maillard Reaction on Fiber Properties.

Dihydromyricetin (DMY) has been encapsulated in delivery systems to address the solubility limitations of DMY in water and improve its bioavailability. Air-assisted electrospinning has been used as a novel technology to load DMY. To evaluate the impact of adding DMY to dextran/zein nanofibers and understand the effects of the Maillard reaction (MR) on the physical and functional properties of DMY-loaded nanofibers, dextran/zein/xylose nanofibers with 0%, 1%, 2%, 3%, and 4% DMY were fabricated, followed by MR crosslinking. Scanning electron microscopy (SEM) observations indicated that the addition of DMY and the MR did not affect the morphology of the nanofibers. X-ray diffraction (XRD) results indicated amorphous dispersion of DMY within the nanofibers and a decreased crystalline structure within the nanofibers following the MR, which might improve their molecular flexibility. The nanofibrous film formed after the MR exhibited both increased tensile strength and elastic modulus due to hydrogen bonding within the nanofibers and increased elongation at break attributed to the increased amorphization of the structure after crosslinking. The nanofibers were also found to exhibit improved heat stability after the MR. The antioxidant activity of the nanofibers indicated a dose-dependent effect of DMY on radical scavenging activity and reducing power. The maintenance of antioxidant activity of the nanofibers after the MR suggested heat stability of DMY during heat treatment. Overall, dextran/zein nanofibers with various DMY contents exhibited tunable physical properties and effective antioxidant activities, indicating that dextran/zein nanofibers offer a successful DMY delivery system, which can be further applied as an active package.

3D Bioprinting of Artificial Skin Substitute with Improved Mechanical Property and Regulated Cell Behavior through Integrating Patterned Nanofibrous Films.

Three-dimensional (3D) bioprinting has advantages for constructing artificial skin tissues in replicating the structures and functions of native skin. Although many studies have presented improved effect of printing skin substitutes in wound healing, using hydrogel inks to fabricate 3D bioprinting architectures with complicated structures, mimicking mechanical properties, and appropriate cellular environments is still challenging. Inspired by collagen nanofibers withstanding stress and regulating cell behavior, a patterned nanofibrous film was introduced to the printed hydrogel scaffold to fabricate a composite artificial skin substitute (CASS). The artificial dermis was printed using gelatin-hyaluronan hybrid hydrogels containing human dermal fibroblasts with gradient porosity and integrated with patterned nanofibrous films simultaneously, while the artificial epidermis was formed by seeding human keratinocytes upon the dermis. The collagen-mimicking nanofibrous film effectively improved the tensile strength and fracture resistance of the CASS, making it sewable for firm implantation into skin defects. Meanwhile, the patterned nanofibrous film also provided the biological cues to guide cell behavior. Consequently, CASS could effectively accelerate the regeneration of large-area skin defects in mouse and pig models by promoting re-epithelialization and collagen deposition. This research developed an effective strategy to prepare composite bioprinting architectures for enhancing mechanical property and regulating cell behavior, and CASS could be a promising skin substitute for treating large-area skin defects.

Hierarchical Porous Reduced Graphene Oxide/Poly(l-lactic acid) Fiber Films: The Influence of Recrystallization on Strength.

Electrospinning technology for fabricating nanofiber films and the Hummer method for synthesizing graphene oxide (GO), along with subsequent reduction, have been significantly advanced, demonstrating immense potential for large-scale industrial applications. Nanofibrous films loaded with reduced graphene oxide (rGO) have been widely explored for their applications in electromagnetic shielding, the biomedical fields, and pollutant adsorption. However, fragile mechanical performance of electrospun fibers with limited surface post-treatment methods has somewhat hindered their further industrial development. In response to this challenge, we propose a dual-regulation strategy involving post-treatment to form porous nanofiber films and the controlled flake size of rGO for surface coating during preparation. This approach aims to achieve poly(l-lactic acid) (PLLA)/rGO electrospun fibrous films with enhanced mechanical properties. It offers a roadmap for the continued application and standardized production of fibrous films loaded with rGO.

A robust, eco-friendly, and biodegradable cellulose nanofiber composite film for highly effective formaldehyde removal at room temperature

Formaldehyde (HCHO) poses a significant threat as a common indoor air pollutant, leading to various health issues. However, effectively addressing HCHO removal at room temperature remains a considerable challenge. This paper presents the preparation of a robust, eco-friendly, and biodegradable composite cellulose nanofiber film, incorporating CeO2-Ag@MnO2 catalysts and TEMPO-oxidized cellulose nanofiber (TOCNF), for high-efficiency HCHO removal at room temperature. A CeO2-Ag@MnO2 ternary catalyst with a core–shell structure was constructed to enhance the catalytic oxidation activity and stability. This structure increased the number of active sites on the catalyst surface and enhanced the interfacial synergistic effect of Ce-Ag-Mn. The TOCNF physically adsorbed HCHO in the composite film, while the catalyst oxidized it to CO2 and water. The composite films, particularly those with 20 wt% CeO2-Ag@MnO2 catalyst, exhibited high HCHO removal rates of 91.2 % at 20 °C and 99.6 % at 60 °C. Furthermore, the TOCNF/20 CAM composite films demonstrated excellent mechanical properties and degradability. This composite film offers an efficient and eco-friendly solution for the catalytic oxidation of HCHO at room temperature.

Effect of SiO2-doped nanoparticle/electrostatic spinning system on the electro-optical properties of polymer dispersed liquid crystals for smart windows

ABSTRACT Polymer Dispersed Liquid Crystal (PDLC) films are attracting increasing attention as versatile and innovative material for use in electrical switching and flexible devices. This paper investigates the effect of a Poly(methyl methacrylate (PMMA) nanospun membrane system doped with SiO2 nanoparticles on the electro-optical properties and transmittance/voltage slopes of thiol- and acrylate-based PDLC films. Experimental samples were prepared for testing by adding mixtures of liquid crystals and crosslinkers in different proportions to liquid crystal cassettes doped with PMMA/SiO2 nanospun membranes. The size of the polymer mesh was found to influence all parameters of PDLC. The phase separation process, which determines the morphology and electro-optical properties of PDLC films, is directly affected by the doping of different components of PMMA/SiO2. The doping of the PMMA/SiO2 system resulted in improved optoelectronic properties of PDLC films, significantly enhanced weathering resistance, and increased the degree of intelligent regulation of the transmittance of PDLC films. Thus, by developing PDLC-doped reticulated nanofibre films with faster response times and better electro-optical properties, the potential for technological applications of PDLC-based devices in optical windows, displays, energy storage and flexible devices can be significantly enhanced.

Nanofiber films reinforced with biomass extracts and their high efficiency in adsorbing dyes

In this study, polyacrylonitrile (PAN) was used as precursor and calcium Lignesulfonate (CLS) as additive to prepare composite films by electrospinning technology for the adsorption of methylene blue (MB) and Congo red (CR) dyes. The composite films were characterized by Brunauer-Emmett-Taylor analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS). The effects of pH value, temperature, concentration and reaction time on adsorption efficiency were investigated. When the content of CLS is 20 wt%, the composite membrane has excellent adsorption performance, and the maximum adsorption capacity of MB and CR are 48 and 23 mg/g.

Visible light-responsive polylactic acid@pullulan-chitosan/homojunction g-C3N4 bilayer antimicrobial films for fruit preservation

The development of novel packaging materials with antimicrobial properties is crucial in preventing the microbial-induced spoilage of fruits, vegetables, and foodborne illnesses. In this study, homojunction g-C3N4 (HCN) photocatalysts with excellent photocatalytic performance were incorporated into a matrix consisting of pullulan/chitosan (Pul/CS). These photocatalysts were then electrostatically spun onto polylactic acid (PLA) films to fabricate PLA@Pul/CS/HCN nanofibrous composite films. The design of the bilayer films aimed to combine the physical properties of PLA film with the excellent antibacterial properties of nanofiber films, thereby achieving synergistic advantages. The incorporation of the HCN photocatalysts resulted in enhanced hydrophobicity, barrier function, and mechanical properties of the composite films. Under visible light irradiation, the PLA@Pul/CS/HCN films exhibited approximately 3.43 log and 3.11 log reductions of Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), respectively, within 2 h. The excellent antimicrobial performance could be attributed to the synergistic effect of CS and the release of reactive oxygen species (ROS) from HCN. Moreover, the strawberries packaged in the PLA@Pul/CS/HCN film demonstrated diminished quality degradation and a prolonged shelf life following visible light irradiation treatment. This study will provide new insights into the exploration of safe and efficient antimicrobial food packaging.

Humidity and pH dual-responsive smart nanofiber antimicrobial packaging

Smart antimicrobial active packaging, capable of responsive release of antimicrobial agents under environmental stimuli, has garnered widespread attention in recent years. This study developed an intelligent active packaging, Cin@PVA/CS-Cin nanofiber films via electrospinning, that exhibits dual-stimuli responsiveness for the release of cinnamaldehyde (Cin) antimicrobial agent. This packaging can respond by releasing Cin in a high-humidity environment during fruit storage to inhibit microbial proliferation. Additionally, in the event of Botrytis cinerea colonization causing a pH decrease, it can further respond by releasing Cin to prevent more fruits from being colonized. Experimental results proved that the Cin@PVA/CS-Cin nanofiber film exhibits excellent humidity and pH responsive capabilities for Cin release, along with outstanding pH-responsive antibacterial and antifungal activity. The preservation experiment on strawberries has confirmed that the film effectively extends the shelf life of strawberries. The enhanced stability and improved antimicrobial performance of this more intelligent multi-responsive antimicrobial active packaging hold significant importance for its practical application in complex environments.

Antibacterial nanofibrous film encapsulated with 4-terpineol/β-cyclodextrin inclusion complexes: Relative humidity-triggered release and shrimps preservation application

Antibacterial active packaging enables extensive biological effects to improve food safety. However, it still remains difficult to achieve controlled and precise release of bioactive compounds to the specific target location with required quantity in food packaging applications. Here, a novel relative humidity (RH) - responsive polyvinyl alcohol/chitosan (PVA/CS) composite nanofibrous film incorporated with 4-terpineol/β-cyclodextrin inclusion complexes (4-TA@β-CD ICs) was engineered by electrospinning that can be exploited as a functional packaging materials. The characterization results showed the thermal stability of the films was enhanced after the incorporation due to the hydrogen bonds between ICs and biopolymers. Besides, the 4 wt% 4-TA@β-CD ICs/PVA/CS film exhibited optimized morphology, crystallinity, mechanical properties, and water vapor permeability. The incorporation of ICs dramatically promoted the antioxidant and inhibition activity of the film especially towards Shewanella putrefaciens. Moreover, the release behavior of 4-TA indicated that high RH accelerated the releasing rate, and the film obtained a sustained-release effect. Finally, the film with long-term antibacterial effectiveness succeeded in extending the shelf life of Litopenaeus vannamei shrimps by an additional 2 days at 4 °C. This work developed a RH-responsive release packaging material, which may serve as an effective active food packaging.

Stable Structure and Fast Ion Diffusion: A Flexible MoO2@Carbon Hollow Nanofiber Film as a Binder-Free Anode for Sodium-Ion Batteries with Superior Kinetics and Excellent Rate Capability.

Designing innovative anode materials that exhibit excellent ion diffusion kinetics, enhanced structural stability, and superior electrical conductivity is imperative for advancing the rapid charge-discharge performance and widespread application of sodium-ion batteries. Hollow-structured materials have received significant attention in electrode design due to their rapid ion diffusion kinetics. Building upon this, we present a high-performance, free-standing MoO2@hollow carbon nanofiber (MoO2@HCNF) electrode, fabricated through facile coaxial electrospinning and subsequent heat treatment. In comparison to MoO2@carbon nanofibers (MoO2@CNFs), the MoO2@HCNF electrode demonstrates superior rate capability, attributed to its larger specific surface area, its higher pseudocapacitance contribution, and the enhanced diffusion kinetics of sodium ions. The discharge capacities of the MoO2@HCNF (MoO2@CNF) electrode at current densities of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 A g-1 are 195.55 (155.49), 180.98 (135.20), 163.81 (109.71), 144.05 (90.46), 121.16 (71.21) and 88.90 (44.68) mAh g-1, respectively. Additionally, the diffusion coefficients of sodium ions in the MoO2@HCNFs are 8.74 × 10-12 to 1.37 × 10-12 cm2 s-1, which surpass those of the MoO2@CNFs (6.49 × 10-12 to 9.30 × 10-13 cm2 s-1) during the discharging process. In addition, these prepared electrode materials exhibit outstanding flexibility, which is crucial to the power storage industry and smart wearable devices.

Tailoring Practical Solid Electrolyte Composites Containing Ferroelectric Ceramic Nanofibers and All-Trans Block Copolymers for All-Solid-State Lithium Metal Batteries.

Ion transport efficiency, the key to determining the cycling stability and rate capability of all-solid-state lithium metal batteries (ASSLMBs), is constrained by ionic conductivity and Li+-migration ability across the multicomponent phases and interfaces in ASSLMBs. Here, we report a robust strategy for the large-scale fabrication of a practical solid electrolyte composite with high-throughput linear Li+-transport channels by compositing an all-trans block copolymer PVDF-b-PTFE matrix with ferroelectric BaTiO3-TiO2 nanofiber films. The electrolyte shows a sustainable electromechanical-coupled deformability that enables the rapid dissociation of anions with Li+ to create more movable Li+ ions and spontaneously transform the battery internal strain into Li+-ion migration kinetic energy. The ceramic framework homogenizes the interfacial potential with electrodes, endowing the electrolyte with a high conductivity of 0.782 mS·cm-1 and stable ion transport ability in ASSLMBs at room temperature. The batteries of LiFePO4/Li can stably cycle 1000 times at 0.5 C with a high capacity retention of 96.1%, and Ah-grade pouch or high-voltage Li(Ni0.8Mn0.1Co0.1)O2/Li batteries also exhibit excellent rate capability and cycling performance.

Effect of tragacanth gum-chitin nanofiber film containing free or nano-encapsulated cumin essential oil on the quality of chilled turkey burgers packed with oxygen absorber.

This research was undertaken to assess the effect of tragacanth gum-chitin nanofiber (TG-CNF) film containing free (CEO) or encapsulated cumin essential oil (CNE) combined with oxygen absorber (OA) packaging on the shelf-life of ready-to-cook (RTC) turkey breast burgers during chilled storage. The experimental groups were OA and TG-CNF as single treatments, TG-CNF + CEO, TG-CNF + CNE, and TG-CNF + OA as binary treatments, TG-CNF + CEO + OA and TG-CNF + CNE + OA as ternary treatments, and control. The samples were stored at 3°C for 20 days and analyzed for microbial, physicochemical, and sensory attributes. Binary treatments, when compared to single treatments, and ternary treatments, when compared to binary treatments, exhibited enhanced effectiveness in managing microbial growth, hindering physicochemical alterations, and decelerating sensory alterations. At day 20, TG-CNF + CNE + OA group was identified as the most effective group in inhibiting the growth of total mesophilic bacteria (TMB), total psychrophilic bacteria (TSB), and coliforms (final counts were 4.8, 4.16, and ≤1 log CFU/g, respectively), and TG-CNF + CNE + OA and TG-CNF + CEO + OA groups were known as the most effective groups in inhibiting lactic acid bacteria (LAB) (final counts were 4.71 and 5.15 log CFU/g, respectively). Furthermore, the TG-CNF + CNE + OA treatment proved to be the most effective group in reducing the total volatile nitrogen (TVN) (final level was 19.2 mg N/100 g) and thiobarbituric acid reactive substances (TBARS) (final level was 0.119 mg malondialdehyde (MDA)/kg). TG-CNF + CNE + OA and TG-CNF + CEO + OA were the most efficient groups to delay the increasing rate of cooking loss (final values were 23.3% and 24.6%) and pH (final values were 7.01 and 6.99). The sample's shelf-life was 4 days in control and TG-CNF, 8 days in OA and TG-CNF + OA, 12 days in TG-CNF + CEO, 16 days in TG-CNF + CNE and TG-CNF + CEO + OA, and at least 20 days in TG-CNF + CNE + OA. As a result, the incorporation of TG-CNF + CNE alongside OA packaging emerges as a highly effective active packaging method for preserving RTC turkey breast burgers during chilled storage.

Development of smart colorimetric indicators for tracking kimchi freshness by loading aronia extract in agar, κ-carrageenan, and cellulose nanofiber films

Color indicator films incorporating aronia extract powder (AEP) and biopolymers like agar, carrageenan, and cellulose nanofiber (CNF) were developed to monitor kimchi freshness. AEP-containing films showed strong UV-barrier properties, and reduced light transmittance by 99.12 % for agar, 98.86 % for carrageenan, and 98.67 % for CNF-based films. All AEP-films exhibited high sensitivity to pH changes and vapor exposure to ammonia and acetic acid. Color change notably influenced by the polymer type, particularly evident with ammonia vapor exposure, especially in the AEP/carrageenan film. The chemical structure and thermal stability of the biopolymers remained unchanged after AEP-addition. Tensile strength increased by 24.2 % for AEP/CNF but decreased by 19.4 % for AEP/agar and 24.3 % for AEP/carrageenan films. AEP-containing films displayed strong antioxidant activity, with 99 % free radical scavenging in ABTS and ~ 80 % in DPPH assays. Alkalized AEP-indicator films were more effective in detecting color changes during kimchi packaging tests. Among the labels, alkalized AEP/agar film showed the most obvious color change from green-gray (fresh kimchi, pH 5.5, acidity 0.48 %) to pale brown (optimal fermentation, pH 4.6, acidity 0.70 %), and pale violet-brown (over-fermented, pH 3.80, acidity 1.35 %). Alkalized AEP-indicator films offer promising real-time detection of packed fermented foods like kimchi.

High performance multifunctional piezoelectric PAN/UiO-66-NO2/MXene composite nanofibers for flexible touch sensor

In this study, a flexible piezoelectric sensor based on polyacrylonitrile (PAN), zirconium-based MOF (UiO-66) with nitro (NO2) and two-dimensional material MXene composite nanofiber film was proposed. When pressure was applied, the three-dimensional structural nanopores were compressed, increasing the intercalation structure between the MXene nanosheets coated in the fibers. The double-packed system produced a higher resistance change under the same pressure load, which can be explained by the fact that the low-conductivity octahedral UiO-66-NO2 particles acted as a similar “buffer” between the highly conductive MXene. At the same time, a large number of hydrogen bonds between the surfaces of the two fillers enhanced the synergistic effect and promoted the interfacial coupling effect, so that more 31-helical conformation in the PAN matrix was converted into a planar zigzag conformation. This improved the piezoelectric performance and enabled the sensor to have a voltage output of about 200 V in the detection range. And because the polyhedral form of UiO-66-NO2 particles provided a rougher surface structure, the piezoelectric sensor can achieve a high sensitivity of 5.62 V/N. The other results showed that the dielectric constant of the designed flexible piezoelectric sensor was increased to 2.67, the dielectric loss was kept at a low level of 0.026, and the maximum elongation was 56.03 %. This multi-functional sensor shows great potential in the fields of health and medical treatment, human-computer interaction, etc.

Asymmetric nanofiber photothermal interactive electronic skin with triboelectric autonomous thermal perceptivity

Thermal-perceptive electronic skins (e-skin) represent an important functional interface in wearables and soft robots. Realizing an all-in-one structured nanofiber interactive e-skin with autonomous thermal perceptivity remains challenging. We demonstrated a polyurethane/(polyvinyl pyrrolidone/MXene) (PPM) bilayer nanofiber film with asymmetric structure compactness by continuous and controllable electrospinning, that achieves asymmetric optical transmittance (visible light transparency of 20∼97%, infrared transparency of 5.5∼34.1%) and photothermal actuation response, with a response rate of 0.8 mm−1 s−1 and bending curvature of 2.2 cm−1, as well as additional excellent triboelectric outputs of ∼320 V and ∼5.4 µA. We proposed a “contact-actuation-perception” strategy for instantaneous object temperature sensing based on the PPM, which can actuate under photothermal stimulation to change its contact area with the target objects at different temperatures, producing temperature-dependent distinguishable triboelectric signals for autonomous thermal perception, with sensitivity up to ∼99.6%. This work could inspire a facile strategy to realize asymmetric features in fiber materials, in which the asymmetric optical-thermal-mechanical-electrical coupling mechanism for active perception is expected to promote the development of autonomous interactive e-skins.

Reconfigurable intelligent surface and switchable electromagnetic interference shield based on dynamically adjustable composite film of cellulose nanofibers and VO2 nanoparticles

The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications.