Nanofiber Films Research Articles

Preparation of transparent electrospun nanofibrous membrane from long‐persistent phosphor‐reinforced polymer for security authentication

AbstractPhotochromic inks have been a tempting authentication method to make commercial items more resistant to counterfeiting. However, recent studies have shown that photochromic inks have major drawbacks, such as expensiveness and low durability. Herein, we report the development of new photochromic nanofibers for cutting‐edge anti‐counterfeiting uses. Lanthanide‐doped strontium aluminate nanoparticles (LSAN) were synthesized and immobilized onto electrospun polyurethane nanofibers (PUNF). Anti‐counterfeiting materials encapsulated with inorganic photochromic agent can guarantee photostability and durability. LSAN function as an efficient inorganic photochromic agent whereas PUNF function as a hosting matrix. Both of photostability and reversibility of the prepared UV‐induced photochromic LSAN@PUNF were found to be rather high. Applying varying ratios of LSAN resulted in the development of polyurethane nanofibers with distinct emission properties depending on the LSAN content. The nanofibrous films showed green emission under UV illumination, and whereas no traces were detected in visible daylight. LSAN displayed diameters of 3–6 nm, whereas LSAN@PUNF nanofibers had diameters of 150–450 nm. Transparency was indicated by an excitation peak at 347 nm, and a green color was indicated by an emission peak of 530 nm. The current approach can be presented as an efficient technology to prevent forgery of commercial products.

Artificial intelligence motivated flexible single-electrode mode multilayer triboelectric sensor for smart mobility systems

Triboelectric tactile sensing technique is increasingly coming into people’s lives to bring convenience, so that there is an urgent necessity for this technique to be applied to smart mobility to increase safety and enhance the mobility experience. Herein, a single-electrode mode multilayer triboelectric sensor (MTS) motivated by artificial intelligence (AI) is proposed, which consists of styrene-butadiene-styrene (SBS)/ poly (vinylida-ene fluoride-trifluoroethylene) (PVDF-TrFE) nanofibers (NFs) film as the friction layer and substrate, laser-induced graphene (LIG)/molybdenum disulfide (MoS2) as the charge trapping layer, and Ag as the electrode. The MTS exhibits remarkable sensing performance, such as a wide response range of 5–100 N, 0.4–2 Hz multi-frequency response capability, and non-contact sensing, as well as distinguished self-powered performance. To demonstrate the practical significance of the proposed MTS, two applications are explored specifically after equipping with AI, including: (i) a smart in-vehicle system is constructed, which consists of unlocking section and multifunctional control with early warning section. (ii) a smart car control system is implemented, which can carry out special tasks instead of humans. These applications provide reliable ways to promote the development of human-machine interaction and smart mobility, as well as help to make lifestyles and mobility smarter, safer and more convenient.

In situ Synthesis of Single Layered Metal-Organic Frameworks via Inkjet Printing on a Cellulose Nanofiber Film.

The inkjet printing is a simple method to develop pattern-controlled 2D metal-organic frameworks (MOFs) due to its cost-effectiveness and ease of operation. Despite the sophisticated structures of MOF crystals, the MOF surfaces are easily contaminated by the adsorption of an ink solution, and the printing nozzle can be clogged by the aggregates of MOFs during printing. Unlike the mixture inks of MOFs and a carrier medium, the surface-specific patterning by in situ synthesis provides the film surface with the controlled patterns of an MOF single layer having different morphologies of MOFs without changing the ink cartridges. It enables facile printing due to the low viscosity of inks and escapes the risk of nozzle clogging because MOFs are synthesized at the printed patterns on the substrates. The ion-exchanged cellulose nanofiber (CNF) films form strong coordination with metal ions enhancing the stability of the MOFs on the film surface. It also demonstrates the controlled coverage of the MOFs by the printing pass number and the carboxylate content of CNF and the tunable adsorption of the guest molecules for different loading capacities of the printed patterns.

High-temperature flexible electric Piezo/pyroelectric bifunctional sensor with excellent output performance based on thermal-cyclized electrospun PAN/Zn(Ac)2 nanofiber mat

High-temperature sensors are critical in petrochemical, aerospace, and automotive industries. However, the inorganic piezoelectric materials for high-temperature sensors are usually rigid and only can work in low temperatures due to their low Curie temperature (< 200 °C), which restricts these sensors for high-temperature application. Herein, we report a high-temperature piezoelectric sensor based on PAN/Zn(Ac)2 composite nanofiber mat created via electrospinning and thermal-oxidative stabilization process, which can continuously work over 500 °C. Moreover, the heat-treatment PAN is first found to be pyroelectric. The effects of the different heat-treatment temperatures on the mechanical and electrical performance of PAN/Zn(Ac)2 composite nanofiber mats are studied systematically. The maximum voltage output of the PAN/Zn(Ac)2 composite film sensor is 14.13 V at room temperature, and the voltage output of the composite film (450 ℃ heat-treated) sensor is about 14.86 V at high temperature. Besides, it has durability for over 10000 cycles (room temperature), and it has durability for over 5000 cycles and stability after 60 days (400 ℃). The PAN/Zn(Ac)2 composite nanofiber film also showed a linear voltage response to the thermal gradient, but the pyroelectric output of the PAN/Zn(Ac)2 composite nanofiber film is independent of the heat treatment temperature. The PAN/Zn(Ac)2 composite film sensor can charge a capacitor and can instantly drive small electronic devices when the capacitor discharges, and the PAN/Zn(Ac)2 composite film sensor can be applied to fire safety. Overall, good flexibility, high-temperature resistance, and bifunctional sensing ability make PAN/Zn(Ac)2-type sensors expected to be widely used in the high-temperature field of fire safety, the automotive industry, and other harsh environment.

Immobilization of natural extract from Humulus lupulus L. in electrospun polyvinyl alcohol nanofibrous membrane for colorimetric determination of ferric

Metallochromic nanofibrous membranes were electrospun from an aqueous solution of xanthohumol (XNS) of Humulus lupulus L. (common hop) extract and polyvinyl alcohol (PVA) for determination of ferric ions. In order to detect ferric ions in aquatic media, a simple, portable, quick, and colorimetric detector was prepared using xanthohumol chromophore as an active spectroscopic detection site encapsulated in PVA nanofibers as a hosting bulk. The CIE Lab color parameters show that binding these poisonous ferric cations to the xanthohumol active detection sites results in a noticeable color shift from yellow (467 nm) to off-white (337 nm). This could be attributed to the creation of a coordination bonds between Fe(III) and phenolic xanthohumol. Increasing the quantity of ferric ions was shown to have a linear effect on the monitored color. The xanthohumol extraction was investigated by High Performance Liquid Chromatography (HPLC). Energy-dispersive X-ray spectrometer (EDX) and scanning electron microscopy (SEM) were employed to characterize the surface morphologies and structural properties of XNS@PVA nanofibers. Electrospun XNS@PVA nanofibrous film with a nanofiber diameter of 75–225 nm was produced. In order to prepare water-insoluble nanofibers, they were exposed to cross-linking with glutaraldehyde fumes. The xanthohumol-containing nanofibers exhibit remarkable ease of use with a detection limit of 0.1–300 ppm. XNS@PVA exhibited high selectivity when compared to various transition metal ions, such as K+, Na+, Ba2+, Zn2+, Cd2+, Hg2+, Co2+, Mn2+, Cu2+, Mg2+, Ni2+, Ca2+, Al3+, and Cr3+. The optimized pH conditions for the detection of Fe(III) were shown to exist between the values of 5 and 7.75. When compared to alternative detection methods, the current assay has the advantages of rapidity, simplicity, cheapness, environmental safety, and ease of operation.

Highly Thermally Conductive Triple-Level Ordered CNT/PVA Nanofibrous Films.

The escalating thermal power density in electronic devices necessitates advanced thermal management technologies. Polymer-based materials, prized for their electrical insulation, flexibility, light weight, and strength, are extensively used in this field. However, the inherent low thermal conductivity of polymers requires enhancement for effective heat dissipation. This work proposes a novel paradigm, emphasizing ordered structures with functional units, to create triple-level, ordered, low-filler loading of multi-walled carbon nanotube (MWCNT)/poly(vinyl alcohol)(PVA) nanofibrous films. By addressing interfacial thermal resistance through -OH groups, the coupling between polymer and MWCNT is strengthened. The triple-level ordered structure comprises aligned PVA chains, aligned MWCNTs, and aligned MWCNT/PVA composite fibers. Focusing on the filler's impact on thermal conductivity and chain orientation, the thermal transport mechanisms have been elucidated level by level. Our MWCNT/PVA composite, with lower filler loadings (10 wt.%), achieves a remarkable TC exceeding 35.4 W/(m·K), surpassing other PVA composites with filler loading below 50 wt.%.

A honeycomb-inspired carboxymethyl chitosan-covalently link NH2-black phosphorene biobased cellulose green nanocomposites with tremendously enhancement fire safety and thermal conductivity

Biobased carboxymethyl chitosan-modified black phosphorene (BP-CMC) was prepared through an amidation reaction between amino group functionalized black phosphorene (NH2-BP) and CMC. Density functional theory (DTF) express that the adsorption energy between urea and phosphene is −6.28 eV, indicating a strong interaction. The resulting BP-CMC was further applied to reinforce the mechanical, flame-retardant and thermal conductivity performance of honeycomb cellulose nanofiber (CNF) film via vacuum filtration. Cone calorimetry test (CCT) result exhibits that the introduction of 30 wt% BP-CMC significantly promoted the fire safety of CNF. For instance, a 98.41% reduction in smoke production rate (SPR), 92.00 % decline in CO release and a 61.31% decrease in heat release rate (HRR) were observed compared to neat CNF. Furthermore, Thermogravimetric infrared (TG-IR) indicates a significant decrease in the release of flammable gases. Raman spectra verify that the incorporation of 30 wt% BP-CMC improves the graphitization degree of residual chars, thus limiting the transfer of heat and oxygen. The improvement in fire safety is attributed to the formation of an intumescent flame-retardant system, which is rich in carbon source (CMC), acid source (BP) and gas source (amino). Simultaneously, the introduction of 30 wt% BP-CMC into CNF leads to considerable enhancement in thermal conductivity (up to 17.49 %), thermal diffusion (utmost to 43.45 %) and heat capacity (increased by 19.23 %). Moreover, the 30 wt % addition of BP-CMC into CNF possesses excellent mechanical properties with the improvement of toughness (increased by 143.50 %) and tensile strength (increased by 140.90 %). This strategy not only provides a new strategy for functionalizing BP but also upgrades the application potential of BP nanosheets in the fire safety of polymer composite films.

N-type semiconductor with energy storage made from chitosan

Chitosan, obtained from crustaceans such as crabs and shrimp, has been mainly used in medicine; however, no studies on its use in electronic applications with semiconducting and large storage properties have been reported. Here, we report an n-type semiconducting biomaterial with energy storage properties of 694.4 mJ/m2 consisting of a chitosan nanofiber (ChNF) film with N-type negative resistance. The ChNF generates an alternative-current wave with a frequency of 7.8 MHz at a threshold voltage of 187 MV/m from a direct-current voltage source, with the switching effect of a third-order resistance change. This is due to the Gunn effect, caused by the repeated voltage-induced generation of a strong electric field domain (electric double layer) at the cathode and its disappearance at the anode of the ChNF device. Electron spin resonance spectral analysis showed that conducting electrons of the ChNF were identified as radicals on the aminyl radical, N·H. Paper electronics made from marine products are a great boon to a renewable society.

A Colorimetric Nanofiber Film Based on Ethyl Cellulose/Gelatin/Purple Sweet Potato Anthocyanins for Monitoring Pork Freshness.

In this study, colorimetric indicator nanofiber films based on ethyl cellulose (EC)/gelatin (G) incorporating purple sweet potato anthocyanins (PSPAs) were designed via electrospinning technology for monitoring and maintaining the freshness of pork. The film presented good structural integrity and stability in a humid environment with water vapor permeability (WVP) of 6.07 ± 0.14 × 10-11 g·m-1s-1Pa-1 and water contact angle (WCA) of 81.62 ± 1.43°. When PSPAs were added into the nanofiber films, the antioxidant capacity was significantly improved (p < 0.05) with a DPPH radical scavenging rate of 68.61 ± 1.80%. The nanofiber films showed distinguishable color changes as pH changes and was highly sensitive to volatile ammonia than that of casting films. In the application test, the film color changed from light pink (fresh stage) to light brown (secondary freshness stage) and then to brownish green (spoilage stage), indicating that the nanofiber films can be used to detect the real-time freshness of pork during storage. Meanwhile, it could prolong the shelf life of pork by inhibiting the oxidation degree. Hence, these results suggested that the EC/G/PSPA film has promising future for monitoring freshness and extending shelf life of pork.

Pullulan nanofibrous films incorporated with W/O emulsions via microfluidic solution blow spinning technology

In this work, pullulan (PUL) nanofibrous films incorporated with water-in-oil emulsions (PE) were prepared by microfluidic blowing spinning (MBS). The microstructures of nanofibers were characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR), and X-ray diffraction (XRD). With the addition of W/O emulsions, the thermal stability, mechanical, and water barrier properties of PUL nanofibers were improved. Increases in emulsion content significantly affected the antioxidant and antimicrobial properties of nanofibrous films. ABTS and DPPH free radical scavenging rates increased from 10.26 % and 8.57 % to 60.66 % and 57.54 %, respectively. The inhibition zone of PE nanofibers against E. coli and S. aureus increased from 11.00 to 20.00 and from 15.67 to 21.17 mm, respectively. In addition, we investigated the freshness effectiveness of PE nanofibrous films on fresh-cut apples. PE nanofibrous films significantly maintained the firmness, and reduced the weight loss and browning index of the fresh-cut apple, throughout the 4 days of storage. Thus, the PE nanofibrous films exhibited good potential to prolong the shelf life of fresh-cut fruit and promote the development of active food packaging.

Zein Multilayer Electrospun Nanofibers Contain Essential Oil: Release Kinetic, Functional Effectiveness, and Application to Fruit Preservation.

In this study, sequential electrospinning was employed to produce a multilayer film consisting of zein nanofibers (Z) and Zataria multiflora essential oil (ZMEO) with different layers. The layers include: Z (without ZMEO), Z1 (one layer of Z + ZMEO), Z3 (three layers of Z + ZMEO), and Z5 (five layers of Z + ZMEO). Then, the effect of this antimicrobial packaging was investigated in relation to increasing the shelf life of strawberries at 4 °C for 12 days. The scanning electron microscopy (SEM) images of the fibers demonstrated a uniform and smooth structure without any beads. The use of Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC) showed that ZMEO was physically encapsulated into multilayer Z, resulting in an enhancement in thermal stability. The multilayer film showed a sustained release pattern of the encapsulated ZMEO for Z3, lasting for 90 h, and Z5, lasting for 180 h. This was in contrast to the rapid release within 50 h observed with Z film. The release kinetics for Z5 showed a good correlation with both the Higuchi and Korsmeyer-Peppas models, while for Z1 and Z3 films, Fickian diffusion was identified as the underlying mechanism. The findings of this study indicated that the multilayer film released ZMEO through a combination of diffusion and polymeric erosion. During a 12-day period of cold storage, strawberries that were treated with Z5 showed significant preservation of their anthocyanin (32.99%), antioxidant activity (25.04%), weight loss (24.46%), titratable acidity (11.47%), firmness (29.67%), and color (10.17%) compared to the control sample. The findings indicated that the sequential electrospinning technique used to create the multilayer nanofibrous film could be used in various fields, such as bioactive encapsulation, controlled release, antimicrobial packaging, and food preservation.

Robust photoelectrocatalytic degradation of antibiotics by organic-inorganic PDISA/Bi2WO6 S-scheme heterojunction membrane

Ensuring the stability of the photoelectrode is paramount for optimal photoelectrocatalysis performance. In this investigation, a hybrid nanofiber film, incorporating the π-π conjugated self-assembly of perylene diimide monomers (PDISA) with Bi2WO6 (PDISA/Bi2WO6), was fabricated through the electrospinning process. Subsequently, this flexible electrospun film was pressed onto a Ni mesh to create a robust PDISA/Bi2WO6 electrode membrane. Results from photoelectrocatalytic studies reveal that the devised PDISA/Bi2WO6 photoanode significantly enhances the photoelectrocatalytic degradation efficiency of tetracycline (TC) and ciprofloxacin (CIP). Specifically, the apparent rate constants for the photoelectrocatalytic degradation of TC by 30%PDISA/Bi2WO6, compared to pristine PDISA and Bi2WO6, are elevated by 1.9 and 2.0 times, respectively. Moreover, the reaction rates of the photoelectrocatalytic (PEC) process surpass those of photocatalysis (PC) and electrocatalysis (EC) by 1.9 times and 8.0 times, respectively. Impressively, even after five cycles of PEC degradation of TC, the photoelectrode maintains 98.4% of its initial degradation rate, indicating its exceptional stability. These improvements in degradation efficiency and stability are attributed to the creation of the PDISA/Bi2WO6 S-scheme heterojunction membrane photoanode and the synergistic effects of photoelectrocatalysis.

Evolving non-aggregated ZIF-8 nanoparticles into hierarchically porous hollow carbon nanofibers for high-performance flexible zinc-ion hybrid supercapacitor

Zinc-ion hybrid supercapacitors are garnering widespread interest in wearable energy storage devices due to their high power density, intrinsic safety and cost-effectiveness. However, the primary obstacle to their progress lies in the scarcity of cathode materials that concurrently demonstrate excellent flexibility and high energy density. Herein, we deliberately design a coaxial electrospinning ZIF-8 derived hollow carbon nanofiber film electrode (C-PAN(ZIF-8)@PVP) to achieve high-performance flexible ZHSCs. The distinctive configuration of C-PAN(ZIF-8)@PVP electrode comprises a shell of homogeneously distributed ZIF-8 derived porous carbon nanoparticles, which are bound together by N-doped carbon fibers derived from polyacrylonitrile (PAN), and a channel through the fiber created by the decomposition of polyvinylpyrrolidone (PVP). This unique architecture coupled with N, O co-doping bestows ample electrolyte infiltration, complete exposure of active sites, and a rapid pathway for electron conduction, resulting in facilitated ion diffusion kinetics, abundant active sites and enhanced electronic conductivity of the C-PAN(ZIF-8)@PVP electrode. As a result, the assembled ZHSC delivers a high reversible capacity of 116 mAh g−1 at 0.1 A g−1 and remarkable capacity retention of 100% over 4000 cycles at 5 A g−1. Moreover, it exhibits exceptional mechanical flexibility, capable of delivering stable output under arbitrary deformation. The intricate structural design strategy offers valuable insights for the development of high-performance electrode materials.

Vanillin-derived epoxy-coated flexible cellulose nanofiber film for multifunctionality and energy harvesting applications

Cellulose nanofiber (CNF), a state-of-the-art sustainable material, often suffers from high hydrophilicity, flammability, and emaciated UV-blocking properties, hampering its broad growth in high-performance applications. This paper reports a novel multifunctional bio-based-epoxy-coated CNF film promising to cope with the addressed challenges. Key to this approach is the etherification reaction, which favors excellent compatibility between CNF film and vanillin-derived epoxy (VDE) resin, resulting in a robust crosslinked network structure with a remarkable adhesion strength (16.12 ± 0.7 MPa), tensile strength (211.6 ± 7.2 MPa), and Young's modulus (8.6 ± 0.4 GPa). A thin VDE layer coating on CNF (VDE/CNF) film significantly presented the film's hydrophobicity of around ⁓93.0 ± 1.5° and UV shielding performance of ⁓100%. Additionally, the coated VDE/CNF film exhibited higher thermal stability (213 °C) and char residue (36%) than the CNF film. Most importantly, despite the high flammability nature of CNF film, the VDE/CNF film passed a V-0 rating under the UL-94 test with a limited oxygen index of 31.8%. The VDE/CNF film was utilized for a triboelectric nanogenerator (TENG) to demonstrate its broad technological impact. Notably, the VDE/CNF-TENG exhibited a significant output power of 18.33 μW. This critical approach offers a promising way to extensively utilize sustainable and multifunctional VDE/CNF nanocomposite materials for high-performance applications.

Mechanically robust and uniform aramid nanofiber films fabricated using repeated spin-coating and protonation processes

Aramid nanofiber (ANF) films show promise for various industrial applications, but their applicability has been constrained by the low mechanical properties, which are mainly due to their incomplete packing and non-uniform microstructure. This work introduces an efficient method for significantly improving the mechanical properties of ANF films using repeated spin coating and protonation. The method allows for the preparation of ANF films with highly uniform microstructures and adjustable thicknesses while achieving excellent mechanical properties. These ANF films have a Young's modulus of 6.8 GPa, tensile strength of 310 MPa and hardness of 248 MPa, surpassing those produced using previous methods. A comprehensive analysis of the surface and cross-sectional morphologies, chemical composition, thermal stability, and mechanical properties was also carried out to characterize the film properties.

Solution blow spun flexible zirconia nanofibers toward high-performance 2D and 3D nanostructures

Polymer templates are critical in the preparation of ceramic fibers from precursor solutions, but the available options are limited. Here, ZrO2 nanofiber films and aerogels are developed by solution blow spinning method using hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) as templates. The effects of HPMC ratio, polymer concentration, and calcination temperature on the morphology and structure of the ZrO2 nanofibers are investigated. The nanofiber films with an areal density of 20 mg cm−2 exhibit excellent filtration property, achieving a filtration efficiency of 94.94% and a pressure drop of 136 Pa at an airflow velocity of 32 L min−1. The nanofiber aerogels display low density of 50 mg cm−3, low thermal conductivity of 0.039 W m−1 K−1, as well as superior compressibility, demonstrating significant potential for thermal protection applications. This work expands the formation template option of ceramic fibers, offering significant guidance in the development of flexible, high-temperature-resistant ceramic fiber materials.

Influence of chitin nanofibers and gallic acid on physical-chemical and biological performances of chitosan-based films

In this work, chitosan films loaded with gallic acid and different content of chitin nanofibers were prepared and subjected to different characterization techniques. The results showed that the inclusion of gallic acid to chitosan films caused moderate decrease in water vapor permeability (by 29 %) and increased tensile strength of films (by 169 %) in comparison to the neat chitosan films. Furthermore, it was found that the addition of chitin nanofibers up to 30 % into chitosan/gallic acid films additionally improved tensile strength (by 474 %) and reduced plasticity of films (by 171 %), when compared to the chitosan/gallic acid films. Increased concentration of chitin nanofibers in films reduced the overall water vapor permeability of films by 51 %. In addition, gallic acid and chitin nanofibers had synergic effect on high chitosan film's antioxidant and antifungal activity toward Botrytis cinerea (both above 95 %). Finally, chitosan/gallic acid/chitin nanofibers films reduced decay incidence of strawberries, increased total soluble solid content, and promoted high production of some polyphenols during cold storage, in comparison to the control chitosan films and uncoated strawberry samples. Hence, these results suggest that chitosan/gallic acid/chitin nanofibers can present eco-sustainable approach for preservation of strawberries, giving them additional nutritional value.

Development of Vitamin C-Loaded Electrospun Nanofibers of Mixture of Polysaccharides of Pullulan/Xanthan Gum for Fast Dissolving Oral Film Applications.

In this study, polysaccharide-based nanofibrous fast dissolving oral films (FDOFs) were developed using pullulan (PUL) and xanthan gum (XG) via electrospinning. The edible, continuous, and bead-free nanofibers with average diameters ranging from 181.17 nm to 260.84 nm were prepared. The morphological, thermal, mechanical, and water-soluble properties of the nanofibrous FDOFs were characterized. For prospective future applications of the developed PUL/XG FDOFs, a model nutrient of vitamin C (VC) was encapsulated into the FDOFs. The success of VC encapsulation was confirmed by Fourier transform infrared spectroscopy. The encapsulation efficiency of VC was above 85% by ultraviolet-visible spectrophotometer. The amorphous structure of PUL/XG in the nanofibers film was demonstrated by X-ray diffractometer. In addition, the edible FDOFs could dissolve in water within 3 s. The nanofibers film we prepared could be used as nutrient or drug carriers and edible packaging film.

Preparation of photoresponsive lanthanide aluminate-immobilized nanofibers from recycled bioplastic via solution blowing spinning for optical authentication labeling

Photochromism is an intriguing technology to enhance the authentication of various commercial materials. In order to produce a transparent authentication film, it is also significant to improve the engineering process of anti-counterfeiting materials. In contrast to electrospinning, the solution blowing spinning (SBS) technique has been recently developed to produce nanofibers at low-cost and high yield with no need to apply high voltage. It has been essential to reduce the toxic pollution caused by plastic waste. Herein, we develop a photoluminescent nanofibrous membrane from recycled polylactic acid (PLA) waste and nanoparticles of strontium aluminate (NSA) by using the simple SBS technique. We investigated the potential use of the NSA@PLA composite nanofibers for photochromic anti-counterfeiting driven by ultraviolet light. Encapsulating the nanoparticle form of the strontium aluminate phosphor into polylactic acid nanofibers is necessary to ensure the transparent characteristic of the nanofibrous film. The film transparency can be further improved by the efficient dispersion of NSA without aggregation in the polylactic acid solution. Nanofibrous membranes with varying emission characteristics were produced by varying the NSA ratio. Both of X-ray diffraction (XRD) and Transmission electron microscopy (TEM) demonstrated the morphology of NSA to show diameters of 5–12 nm. The morphologies of the nanofibrous membranes were examined using various analytical methods, including energy-dispersive X-ray spectroscopy (EDX), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy (SEM). The mechanical characteristics and optical luminescence were also examined. SEM analysis of the NSA@PLA nanofibers showed diameters of 100–220 nm. The NSA@PLA nanofibrous membranes exhibited an emission peak at 518 nm upon excitation at 365 nm. The contact angles of the NSA@PLA nanofibrous membranes increased from 138.2° to 144.5° as the NSA concentration was increased, indicating an improved superhydrophobicity. Exposure to ultraviolet light caused the transparent nanofibers to undergo a rapid and strongly reversible photochromism to greenish emission. The present study can be reported as an easy and efficient approach to create anti-counterfeiting materials that offer a perfect market with social and financial profits.

Effect of Poling on β-Phase Structure of Electrospun PVDF-TrFE Nanofiber Film

Effect of Poling on β-Phase Structure of Electrospun PVDF-TrFE Nanofiber Film