Nanofiber Films Research Articles

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.

Risperidone/cyclodextrin inclusion complex electrospun nanofibers for fast-disintegrating antipsychotic drug delivery

In this paper, the inclusion complexes (ICs) of hydroxypropyl-beta-cyclodextrin (HPβCD) and risperidone were electrospun into nanofibrous film for potential fast-disintegrating drug delivery system. Risperidone is used to treat bipolar disorder, schizophrenia, and mood swings from autism. However, it is practically insoluble in aqueous medium. On the other hand, the encapsulation of risperidone into HPβCD cavity by inclusion complexation can enhance water solubility of this drug molecule. Here, the IC systems were prepared with 4/1 and 2/1 M ratio (HPβCD/risperidone). The highly concentrated HPβCD aqueous solutions (200 %, w/v) were used for the fiber formation. Finally, the system having 4/1 M ratio resulted in a clear and homogeneous solution showing that the HPβCD and risperidone completely formed IC. However, HPβCD/risperidone-IC having 2/1 M ratio was turbid and contained some small clumps of un-complexed risperidone. Even so, free-standing and thin nanofibrous films were obtained for both systems with an average fiber diameter of ∼315 nm and ∼280 nm for 2/1 and 4/1 systems, respectively. Both HPβCD/risperidone-IC nanofibers were produced with approximately 100 % preservation of risperidone within the nanofiber matrix without the loss of risperidone during electrospinning process, that is, HPβCD/risperidone-IC nanofibers retained the initial M ratio of 2/1 and 4/1 as in electrospinning solution. Both HPβCD/risperidone-IC nanofibrous films showed fast-disintegration and fast-release characteristics in artificial saliva and aqueous medium verifying their potential as a fast-disintegrating oral drug delivery system for risperidone.

Novel cellulose-based films with highly efficient photothermal performance for sustainable solar evaporation and solar-thermal power generation

Solar-driven interfacial evaporation has received substantial attention in a variety of applications, including water purification, seawater desalination, and energy production. However, creating a straightforward, adaptable, and scalable method for correctly integrating hybrid solar-thermal systems continues to be a challenging task. Herein, we propose an economical, scalable, and environmentally friendly approach for achieving synergistic coupling of interfacial solar energy conversion for evaporation and low-grade thermal energy conversion to electricity by incorporating zinc oxide (ZnO) nanoparticle-modified MXene (ZNM- MXene) into cellulose nanofiber (CNF) films. The vacuum filtering approach produces CNF@ZNM-MXene composite films with enhanced photothermal conversion efficiency, capillary hydrophilicity, and thermal localization. Because of its rapid water transport capability, excellent sunlight absorption, and efficient solar-thermal conversion under 1 kW m−2 irradiance, the CNF@ZNM-MXene solar evaporator's evaporation rate reaches 1.27 kg m−2 h−1, and the solar-vapor conversion efficiency is as high as 82.15%, outperforming most previously reported solar evaporators. Moreover, when compared to a standalone thermoelectric (TE) module, the output power of the solar thermal conversion system coupled with a CNF@ZNM-MXene composite films and a TE module is boosted by 15.32 times. This work offers a practical and effective method for simultaneously capturing solar energy and desalinating saltwater.

Nanofiber Hydrogel Drug Delivery System for Prevention of Postsurgical Intestinal Adhesion.

Intestinal adhesion is one of the complications that occurs more frequently after abdominal surgery. Postsurgical intestinal adhesion (PIA) can lead to a series of health problems, including abdominal pain, intestinal obstruction, and female infertility. Currently, hydrogels and nanofibrous films as barriers are often used for preventing PIA formation; however, these kinds of materials have their intrinsic disadvantages. Herein, we developed a dual-structure drug delivery patch consisting of poly lactic-co-glycolic acid (PLGA) nanofibers and a chitosan hydrogel (NHP). PLGA nanofibers loaded with deferoxamine mesylate (DFO) were incorporated into the hydrogel; meanwhile, the hydrogel was loaded with anti-inflammatory drug dexamethasone (DXMS). The rapid degradation of the hydrogel facilitated the release of DXMS at the acute inflammatory stage of the early injury and provided effective anti-inflammatory effects for wound sites. Moreover, PLGA composite nanofibers could provide sustained and stable release of DFO for promoting the peritoneal repair by the angiogenesis effects of DFO. The in vivo results indicated that NHP can effectively prevent PIA formation by restraining inflammation and vascularization, promoting peritoneal repair. Therefore, we believe that our NHP has a great potential application in inhibition of PIA.

Layer-by-layer assembly of boron arsenide and copper nanoflake-based aramid nanofibers for thermoconductive electromagnetic interference shielding materials with superior mechanical flexibility and flame retardancy

Flexible and wearable electronics represent an emerging frontier, but realizing their potential requires addressing challenges like electromagnetic interference (EMI) shielding, electrical insulating thermal management, and mechanical flexibility. Layer-by-layer structure with alternating conductive and insulating layers offers a promising solution. In this work, we fabricated layer-by-layer structured papers combining boron arsenide (BA) as insulating layers and two-dimensional copper nanoflake (CuF) as conductive layers based on aramid nanofiber (ANF) film via alternating vacuum filtration. The resultant paper (BA4/CuF3) consists of 3 layers of CuF (50 wt%) based ANF (CuF@ANF) conductive layers sandwiched between 4 layers of BA (50 wt%) based ANF (BA/ANF) insulating layers providing exceptional EMI shielding effectiveness (SE) up to 52 dB in the X-band frequency, and in-plane thermal conductivity up to 32.8 W/mK. Meanwhile, the composite papers also demonstrate excellent mechanical flexibility, with the BA4/CuF3 papers exhibiting a tensile strength of 92.38 MPa and EMI SE above 50 dB. Moreover, the composites impart thermal stability up to 500 °C and reduce flammability. The concurrent enhancement of EMI shielding, thermal conductivity, and mechanical properties confirms the potential of layer-by-layer BA/CuF papers for next-generation flexible electronics demanding electromagnetic protection and thermal management.

Sandwich-Structured Mxene/Waste Polyurethane Foam Composites For Highly Efficient Electromagnetic Interference, Infrared Shielding and Joule Heating.

Electromagnetic interference (EMI) shielding and infrared (IR) stealth materials have attracted increasing attention owing to the rapid development of modern communication and military surveillance technologies. However, to realize excellent EMI shielding and IR stealth performance simultaneously remains a great challenge. Herein, a facile strategy is demonstrated to prepare high-efficiency EMI shielding and IR stealth materials of sandwich-structured MXene-based thin foam composites (M-W-M) via filtration and hot-pressing. In this composite, the conductive Ti3C2Tx MXene/cellulose nanofiber (MXene/CNF) film serves as the outer layer, which reflects electromagnetic waves and reduces the IR emissivity. Meanwhile, the middle layer is composed of a porous waste polyurethane foam (WPUF), which not only improves thermal insulation capacity but also extends electromagnetic wave propagation paths. Owing to the unique sandwich structure of "film-foam-film", the M-W-M composite exhibits a high EMI shielding effectiveness of 83.37dB, and in the meantime extremely low emissivity (22.17%) in the wavelength range of 7-14µm and thermal conductivity (0.19W m-1 K-1), giving rise to impressive IR stealth performance at various surrounding temperatures. Remarkably, the M-W-M composite also shows excellent Joule heating properties, capable of maintaining the IR stealth function during Joule heating.

Cellulose Nanofiber Films with Gold Nanoparticles Electrostatically Adsorbed for Facile Surface-Enhanced Raman Scattering Detection.

Cellulose nanofiber (CNF) holds great promise in applications such as surface-enhanced Raman scattering (SERS), catalysis, esthesia, and detection. This study aimed to build novel CNF-based SERS substrates through a facile synthetic method. Citrate-reduced gold nanoparticles (AuNPs) were adsorbed on the cationized CNF surface due to electrostatic interactions, and uniform AuNPs@(2,3-epoxypropyl trimethylammonium chloride)EPTMAC@CNF flexible SERS substrates were prepared by a simple vacuum-assisted filtration method. The probe molecule methylene blue was chosen to assess the performance of the CNF-based SERS substrate with a sensitivity up to 10-9 M, superior signal reproducibility (relative standard deviation (RSD) = 4.67%), and storage stability (more than 30 days). Tensile strength tests indicated that the CNF-based films had good mechanical properties. In addition, CNF-based substrates can easily capture and visually identify microplastics in water. These results demonstrate the potential application of the flexible, self-assembled AuNPs@EPTMAC@CNF flexible SERS substrate for prompt and sensitive detection of trace substances.

Aramid Nanofiber and Boron Nitride Nanosheet Composite Films for Mechanical and Dielectric Insulation Application

Aramid Nanofiber and Boron Nitride Nanosheet Composite Films for Mechanical and Dielectric Insulation Application

Triboelectric nanogenerator for Self-Powered musical instrument sensing based on the Ion-Electricfield-Migration Nylon/Na2SO4 nanofiber film

The advanced sensing technologies have a significantly important influence in promoting the design and research of intelligent musical instruments. Herein, we propose an ion-electricfield-migration enhanced triboelectric nanogenerator (IE-TENG) with the features of low-cost, lightweight and high-sensitive for the sensors of intelligent musical instruments. Compared to pure nylon nanofiber films, the voltage of IE-TENG with the nylon/Na2SO4 nanofiber films has been improved by 4.5 times, which is benefiting from the improved electrostatic induction of anions and cations migration. The fabricated IE-TENG sensor can achieve an excellent sensing performance with a sensitivity of 7.29 V N−1, a signal-to-noise ratio of 68.61 dB and a response-time of 10 ms, which are several times higher than the previous research works. Importantly, combined with the array structure design, multi-channel data acquisition and artificial intelligence digital analysis, an intelligent musical instrument system is constructed to gather and analyze the performer's playing information in real-time and quickly give the corresponding evaluation and improvement suggestions. Our finding not only give a good way for fabricating excellent performance TENG, but also promotes the application of TENG in intelligent musical instruments.

Electrospun superhydrophobic polyvinyl chloride /polydimethylsiloxane-nanodiamond nanocomposite with enhanced antifouling and mechanical properties for fresh produce packaging

Food package films serve the important functions of preserving food quality, extending shelf life, and protecting against external contaminants while also providing a barrier to moisture and oxygen. In consideration of the increasing frequency of foodborne outbreaks, there is a growing demand for food packaging films with additional functionality to prevent cross-contamination and the attachment of pathogens, thereby enhancing bacterial safety. Herein, we report a one-step fabrication approach relying on electrospinning of a blend of polyvinyl chloride (PVC) and polydimethylsiloxane (PDMS) together with nanodiamond (ND) on a rotating drum collector for the formation of bacterially antifouling food package films. In this approach, by adjusting the concentrations of PVC, PDMS, and ND and the drum angular velocity, the nanofiber diameter could be tuned in the range of 0.4 μm to 2.0 μm. Furthermore, these process parameters could also be used to modulate the water contact angle on the resultant films, with a minimum contact angle of 136.2 ± 5.6° and a maximum of 159.5 ± 3.8°. The lowest water contact angles were observed for films with bare PVC fibers while the highest contact angles were seen for films with nanocomposite fibers containing ND and PVC/PDMS. Compared with the films with bare PVC, nanocomposite films with ND-PVC/PDMS achieved up to 99.8 % and 99.6 % reduction in bacterial adhesion against S. typhimurium LT2 and Listeria innocua, respectively. The tensile strength of nanofibrous PVC film can be increased from 1.2 ± 0.4 MPa to 4.4 ± 0.3 MPa by the inclusion of PDMS (1:1 wt.%) and further increased to 8.9 ± 0.3 MPa with the additional inclusion of ND (PVC/PDMS/ND 1:1:0.1 wt.%). Considering the notable antifouling properties against bacteria and the improved mechanical characteristics, these nanocomposite films represent a noteworthy step in the development of sustainable and active food packaging solutions for a safer and healthier food supply chain.

Preparation, characterization, and the antimicrobial activity of PVA-PVP/ZnO nanofiber films via indigenous electrospinning setup

The study aimed to produce composite nanofibers (NFs) using the electrospinning method from Polyvinyl alcohol- Polyvinylpyrrolidone/Zinc oxide (PVA-PVP/ZnO) solutions. X-ray diffraction analysis confirmed that in the composite nanofibers, the relative intensity of the dominant crystal plane (101) associated with the wurtzite hexagonal structure of ZnO nanoparticles (NPs) decreased, and its broadness increased in the composite, indicating the presence of an amorphous part in the sample. The existence of functional groups from polymer systems was confirmed by Fourier-transform infrared spectroscopy (FTIR) spectral analysis. Field emission scanning electron microscope (FESEM) images revealed linear and branched uniform nanofiber structures with smooth surfaces of PVA-PVP/ZnO electrospun. The absorbance of PVA-PVP/ZnO NFs increased with the increase in ZnO NPs content, and an absorption band was observed in the ultra violet (UV) region at around 310 nm. The calculation of the optical energy gap using the absorption spectra fitting (ASF) approach roughly aligned with Tauc's model, ranging from 3.47 to 3.24 eV. The highest inhibition zone (14 and 15 mm) was observed at the ratios of 4 and 6 wt.% of ZnO NPs against gram-negative bacteria (Escherichia coli).