Electrospun Products Research Articles

Controlling Mechanical Properties of Medical-Grade Scaffolds through Electrospinning Parameter Selection.

Electrospinning (ES) is a versatile process mode for creating fibrous materials with various structures that have broad applications ranging from regenerative medicine to tissue engineering and surgical mesh implants. The recent commercialization of this technology for implant use has driven the use of resorbable electrospun products. Resorbable electrospun meshes offer great promise as temporary implants that can utilize the layer upon layer method of additive manufacturing to incorporate porosity as a function of process parameters into a scaffold structure. The interconnected porosity and feature size known to ES have previously been observed to hold great potential for simulating the natural cellular environment of soft tissue. This microstructure, proper degradation kinetics, and mechanical properties combine to provide the design basis for artificial tissue structures that could aid in not only wound healing but also true tissue engineering and regenerative medicine. While current advancement in the field is understood to be limited by material properties, the importance of optimizing mechanical properties with currently available materials should not be overlooked. This work investigated the process parameter effects and interactions that control the structure-property relationship for a range of medical-grade aliphatic polyester materials with a range of intrinsic properties. An ε-caprolactone homopolymer (PCL), l-lactide homopolymer (PLLA), and Lactoflex, a copolymer with intermediate properties relative to the homopolymers, were characterized before, during, and after the additive manufacturing process. The interacting effects of process parameters, distance to collector, and dispensing rate were shown to produce variable-density, nonwoven scaffold structures. The resorbable mesh scaffolds of PLLA, PCL, and Lactoflex demonstrated a broad range of mechanical properties (approximately 1-10 MPa ultimate tensile strength and 5-390 MPa tensile modulus). Postprocessing of scaffolds demonstrated removal of solvents and preservation of micrometer-sized features. Resorbable polymers and electrospinning can produce scaffold materials with excellent features and offer tremendous potential in the field of implantable resorbable devices.

Fabrication of bacterial cellulose/PVP nanofiber composites by electrospinning.

This study aimed to address a significant challenge in the application of bacterial cellulose (BC) within tissue engineering and regenerative medicine by tackling its inherent insolubility in water and organic solvents. Our team introduced a groundbreaking approach by utilizing zinc sulfate (ZnSO4) as a solvent to render BC soluble, a novel contribution to the literature. Subsequently, the obtained soluble BC was combined with varying concentrations of polyvinylpyrrolidone (PVP). Notably, we pioneered the fabrication of BC/PVP composite scaffolds with customizable fiber surface morphology and regulated degradation rates through the electrospun technique. Several key parameters, such as PVP concentration (8%, 15%, 12%, and 20% w/v), applied voltage (22, 15, and 12 kV), and a fixed nozzle-collector distance of 10 cm with a flow rate of 0.9 mL/h, were systematically evaluated so as to find the optimum parameter created BC/PVP product with electrospun. For electrospun BC/PVP products, a voltage of 12 kV was found to be optimal. Intriguingly, our findings revealed enhanced cell adhesion and proliferation in BC/PVP electrospun products compared with using PVP membranes alone. Specifically, cell viability for PVP and PVP/BC electrospun products was determined as 50.73% and 79.95%, respectively. In terms of thermal properties, the BC/PVP electrospun product exhibited a mass loss of 82.6% at 380°C, while PVP alone experienced 90.2% mass loss at around 280°C. Furthermore, the protein adhesion capacities were measured at 62.3 ± 1.2 μg for PVP and 99.4 ± 2 μg for BC/PVP electrospun products, whereas product showed no biodegradation over 28 days and had notable water retention capacity. In conclusion, our research not only successfully attained nanofiber morphology but also showcased enhanced cell attachment and proliferation on the BC/PVP electrospun product.

The Incorporated Drug Affects the Properties of Hydrophilic Nanofibers.

Hydrophilic nanofibers offer promising potential for the delivery of drugs with diverse characteristics. Yet, the effects of different drugs incorporated into these nanofibers on their properties remain poorly understood. In this study, we systematically explored how model drugs, namely ibuprofen, carvedilol, paracetamol, and metformin (hydrochloride), affect hydrophilic nanofibers composed of polyethylene oxide and poloxamer 188 in a 1:1 weight ratio. Our findings reveal that the drug affects the conductivity and viscosity of the polymer solution for electrospinning, leading to distinct changes in the morphology of electrospun products. Specifically, drugs with low solubility in ethanol, the chosen solvent for polymer solution preparation, led to the formation of continuous nanofibers with uniform diameters. Additionally, the lower solubility of metformin in ethanol resulted in particle appearance on the nanofiber surface. Furthermore, the incorporation of more hydrophilic drugs increased the surface hydrophilicity of nanofiber mats. However, variations in the physicochemical properties of the drugs did not affect the drug loading and drug entrapment efficiency. Our research also shows that drug properties do not notably affect the immediate release of drugs from nanofibers, highlighting the dominant role of the hydrophilic polymers used. This study emphasizes the importance of considering specific drug properties, such as solubility, hydrophilicity, and compatibility with the solvent used for electrospinning, when designing hydrophilic nanofibers for drug delivery. Such considerations are crucial for optimizing the properties of the drug delivery system, which is essential for achieving therapeutic efficacy and safety.

Na3MnTi(PO4)3/C Nanofiber Free-Standing Electrode for Long-Cycling-Life Sodium-Ion Batteries.

Self-standing Na3MnTi(PO4)3/carbon nanofiber (CNF) electrodes are successfully synthesized by electrospinning. A pre-synthesized Na3MnTi(PO4)3 is dispersed in a polymeric solution, and the electrospun product is heat-treated at 750 °C in nitrogen flow to obtain active material/CNF electrodes. The active material loading is 10 wt%. SEM, TEM, and EDS analyses demonstrate that the Na3MnTi(PO4)3 particles are homogeneously spread into and within CNFs. The loaded Na3MnTi(PO4)3 displays the NASICON structure; compared to the pre-synthesized material, the higher sintering temperature (750 °C) used to obtain conductive CNFs leads to cell shrinkage along the a axis. The electrochemical performances are appealing compared to a tape-casted electrode appositely prepared. The self-standing electrode displays an initial discharge capacity of 124.38 mAh/g at 0.05C, completely recovered after cycling at an increasing C-rate and a coulombic efficiency ≥98%. The capacity value at 20C is 77.60 mAh/g, and the self-standing electrode exhibits good cycling performance and a capacity retention of 59.6% after 1000 cycles at 1C. Specific capacities of 33.6, 22.6, and 17.3 mAh/g are obtained by further cycling at 5C, 10C, and 20C, and the initial capacity is completely recovered after 1350 cycles. The promising capacity values and cycling performance are due to the easy electrolyte diffusion and contact with the active material, offered by the porous nature of non-woven nanofibers.

The role of BSA protein on the skin regeneration ability of electrospun PCL/HA scaffolds, kinetics of release and essential in vitro tests

This study focused on the skin regeneration ability of hybrid polycaprolactone (PCL) scaffolds incorporated by hydroxyapatite (HA) nanoparticles (NPs) and bovine serum albumin (BSA). The scaffolds were synthesized by the electrospinning method, and their microstructure, molecular groups, wettability, swelling, porosity, and mechanical properties were characterized. The results showed that the HA NPs and BSA protein could be incorporated within the PCL fibers without a significant effect on the main molecular groups of the PCL structure. Incorporation of both the HA NPs and BSA protein could reduce the superhydrophobicity of the PCL scaffold to the required amount for skin regeneration. It was also found that the incorporation of mentioned elements increased the water uptake by PCL fibrous scaffolds, and decreased the mechanical properties. The kinetics of BSA release from the hybrid scaffolds was also investigated. The Higuchi model was the best-fitting model to explain the protein release from the electrospun products. The cytocompatibility of scaffolds was evaluated by the human umbilical vein endothelial cells (HUVEC), and the higher ability of the PCL/BSA scaffold for skin regeneration was confirmed.

Highly efficient separation of water-in-oil emulsion using electrospun helicoidal polymer strips

Rationally designed electrospun membranes are commonly used to efficiently separate water-in-oil emulsions. However, obtaining high separation efficiency without sacrificing separation flux cannot be readily attained. Herein, we propose a strategy for controlling the overall geometry of the electrospun product to simultaneously achieve high water-in-oil emulsion separation flux and efficiency. Polycaprolactone (PCL)/polyvinylpyrrolidone (PVP) strips with multi-scale helicoidal structures were readily prepared by using immersion electrospinning. The multi-scale helicoidal structure of the strip could be precisely regulated by controlling the PCL/PVP weight ratio and the applied voltage. The desired helicoidal structure of the immersion electrospun strip provided preferred membrane porosity and thickness, as well as multifaceted wettability, leading to a high water-in-oil emulsion separation flux of 2350 L/m2h and a high separation efficiency of over 99 %. After 10 cycles, the separation flux of the immersion electrospun membrane was still around 60 % higher than that of the non-recycled conventional electrospun membrane without sacrificing separation efficiency. Moreover, the mechanisms responsible for the excellent performance of immersion electrospun membranes are discussed in depth. This work offers new insight into the rational preparation of advanced electrospun membranes for oil/water separation applications.

Electrospinning of pullulan-based orodispersible films containing sildenafil

Feasibility of electrospinning in the manufacturing of sildenafil-containing orodispersible films (ODFs) intended to enhance oxygenation and to reduce pulmonary arterial pressure in pediatric patients was evaluated. Given the targeted subjects, the simplest and safest formulation was chosen, using water as the only solvent and pullulan, a natural polymer, as the sole fiber-forming agent. A systematic characterization in terms of shear and extensional viscosity as well as surface tension of solutions containing different amounts of pullulan and sildenafil was carried out. Accordingly, electrospinning parameters enabling the continuous production, at the highest possible rate, of defect-free fibers with uniform diameter in the nanometer range were assessed. Morphology, microstructure, drug content and relevant solid state as well as ability of the resulting non-woven films to interact with aqueous fluids were evaluated. To better define the role of the fibrous nanostructure on the performance of ODFs, analogous films were produced by spin- and blade-coating and tested. Interestingly, the disintegration process of electrospun products turned out to be the fastest (i.e. occurring within few s) and compliant with Ph. Eur. and USP limits, making relevant ODFs particularly promising for increasing sildenafil bioavailability, thus lowering its dosages.

Influence of Polymer Concentration on Drying of SPION Dispersions by Electrospinning.

To improve the physical stability of nanoparticle dispersions, several methods for their transformation into stable and easily dispersible dry products have been investigated thus far. Recently, electrospinning was shown to be a novel nanoparticle dispersion drying method, which addresses the crucial challenges of the current drying methods. It is a relatively simple method, but it is affected by various ambient, process, and dispersion parameters, which impact the properties of the electrospun product. The aim of this study was, thus, to investigate the influence of the most important dispersion parameter, namely the total polymer concentration, on the drying method efficiency and the properties of the electrospun product. The formulation was based on a mixture of hydrophilic polymers poloxamer 188 and polyethylene oxide in the weight ratio of 1:1, which is acceptable for potential parenteral application. We showed that the total polymer concentration of prior-drying samples is closely related to their viscosity and conductivity, also affecting the morphology of the electrospun product. However, the change in morphology of the electrospun product does not affect the efficiency of SPION reconstitution from the electrospun product. Regardless of the morphology, the electrospun product is not in powder form and is therefore safer to handle compared to powder nanoformulations. The optimal total polymer concentration in the prior-drying SPION dispersion, which enables the formation of an easily dispersible electrospun product with high SPION-loading (65% (w/w)) and fibrillar morphology, was shown to be 4.2% (w/v).

Efficient removal of methylene blue from aqueous solution by ZIF-8-decorated helicoidal electrospun polymer strips

Immobilization of metal-organic frameworks (MOFs) on electrospun products for wastewater treatment has garnered considerable attention in recent years. However, the effect of the overall geometry and surface-area-to-volume ratio of MOF-decorated electrospun architectures on their performances have rarely been investigated. Herein, we prepared polycaprolactone (PCL)/polyvinylpyrrolidone (PVP) strips with helicoidal geometries via immersion electrospinning. By regulating the weight ratio of PCL to PVP, the morphologies and surface-area-to-volume ratios of the PCL/PVP strips could be controlled precisely. Then, the zeolitic imidazolate framework-8 (ZIF-8) for removing methylene blue (MB) from an aqueous solution was immobilized on the electrospun strips, resulting in ZIF-8-decorated PCL/PVP strips. The key characteristics of these composite products, such as adsorption and photocatalytic degradation behavior toward MB in the aqueous solution, were carefully investigated. Owing to the desired overall geometry and high surface-area-to-volume ratio of the ZIF-8-decorated helicoidal strips, a high MB adsorption capacity of 151.6 mg g−1 was obtained, which is significantly higher than those with conventional electrospun straight fibers. In addition, higher MB uptake rates, higher recycling and kinetic adsorption efficiencies, higher MB photocatalytic degradation efficiencies, and faster MB photocatalytic degradation rates were confirmed. This work provides new insights to improve the performance of existing and potential electrospun product-based water treatment strategies.

Biodegradable Polymer Electrospinning for Tendon Repairment.

With the degradation after aging and the destruction of high-intensity exercise, the frequency of tendon injury is also increasing, which will lead to serious pain and disability. Due to the structural specificity of the tendon tissue, the traditional treatment of tendon injury repair has certain limitations. Biodegradable polymer electrospinning technology with good biocompatibility and degradability can effectively repair tendons, and its mechanical properties can be achieved by adjusting the fiber diameter and fiber spacing. Here, this review first briefly introduces the structure and function of the tendon and the repair process after injury. Then, different kinds of biodegradable natural polymers for tendon repair are summarized. Then, the advantages and disadvantages of three-dimensional (3D) electrospun products in tendon repair and regeneration are summarized, as well as the optimization of electrospun fiber scaffolds with different bioactive materials and the latest application in tendon regeneration engineering. Bioactive molecules can optimize the structure of these products and improve their repair performance. Importantly, we discuss the application of the 3D electrospinning scaffold's superior structure in different stages of tendon repair. Meanwhile, the combination of other advanced technologies has greater potential in tendon repair. Finally, the relevant patents of biodegradable electrospun scaffolds for repairing damaged tendons, as well as their clinical applications, problems in current development, and future directions are summarized. In general, the use of biodegradable electrospun fibers for tendon repair is a promising and exciting research field, but further research is needed to fully understand its potential and optimize its application in tissue engineering.

Hollow/sponge-core β-carotene-poly-vinylpyrrolidone (PVP) Electrospun Fibers using High-pressure CO2 Electrospinning

Polyvinylpyrrolidone (PVP) is used in various applications because of its unique chemical and physical properties, including biocompatibility and low toxicity. In this study, we successfully prepared ethanol solution-based hollow-core β-carotenoid PVP fibers using high-pressure carbon dioxide (CO2) at 5 MPa and 318 K ambient temperature, a polymer solution at 333 K, an 8-cm tip-to-collector distance, and DC voltage of 15 kV. In this study, the morphological and physical properties of the electrospun products were investigated by using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) scanning spectroscopy, X-ray diffraction (XRD), and differential scanning calorimetry (DSC).

Electrospinning as a method for preparation of redispersible dry product with high content of magnetic nanoparticles

One of the key technological challenges in the development of iron-oxide-based magnetic nanoparticles (MNPs) is their long-term physical stability in colloidal dispersions. This can be improved by their transformation into a dry form. Here, we introduce electrospinning as a drying method for ethanol-based and water-based MNP dispersions, which enables the preparation of high-loaded dry MNP products. The obtained easily dispersible electrospun product contained up to 50 % (w/w) of MNPs, homogeneously distributed in the fibrillar structure, which is much more compared to the products of currently available methods for drying MNP dispersions. The polymers used as building blocks of nanofibers, namely poloxamer 188 and polyethylene oxide, improved the tolerance of MNPs to high ionic strength dispersion medium and thus enhanced the short-term physical stability of MNP dispersions after reconstitution. The dry product was stable for up to 1 month at room temperature and relative humidity up to 70 %. It was in the form of a nanofiber mat, which prevented the aerosolization of MNPs and their unintentional ambient exposure. Therefore, the electrospun product with MNPs is expected to be a safer dry formulation of MNPs than the nanoparticulate powders, which are usually the final products of the conventional drying methods.

Electrospinning of botanicals for skin wound healing.

Being the first barrier between the human body and external environments, our skin is highly vulnerable to injuries. As one of the conventional therapies, botanicals prepared in different topical formulations have been applied as medical care for centuries. With the current increase of clinical requirements, applications of botanicals are heading towards nanotechnologies, typically fused with electrospinning that forms nanofibrous membranes suitable for skin wound healing. In this review, we first introduced the main process of wound healing, and then presented botanicals integrated into electrospun matrices as either loaded drugs, or carriers, or membrane coatings. In addition, by addressing functional features of individual botanicals in the healing of injured skin, we further discussed the bioactivity of botanical electrospun membranes in relevant to the medical issues solved in the process of wound healing. As achieved by pioneer studies, due to infrequent adverse effects and the diversity in resources of natural plants, the development of electrospun products based on botanicals is gaining greater attention. However, investigations in this field have mainly focused on different methodologies used in the preparation of nanofibrous membranes containing botanicals, their translation into clinical practices remains unaddressed. Accordingly, we propose that potential clinical applications of botanical electrospun membranes require not only the further expansion and understanding of botanicals, but also an establishment of standard criteria for the evaluation of wound healing and evolutions of technologies to support the large-scale manufacturing industry.

Morphology evolution of self‐same nanocomposites hybridized with jumbo‐sized particles

AbstractThis article reports the production, morphological analyzes, and application of electrospun self‐same nanocomposites with milled carbon fibers (MCFs). The new hybridized structure was also incorporated into conventional fiber reinforced epoxy composites with improved properties. The MCF‐hybridized polymeric nonwoven mats were formed with the simultaneous dual electrospinning of a soften‐able (m‐phase) and a crosslink‐able (x‐phase) variants of poly(styrene‐co‐glycidyl methacrylate). The morphology of the hybrid material was investigated using scanning electron microscopy (SEM). The results showed that electrospinning can successfully deposit reinforcing particles of giant size (MCFs are 7 μm in diameter, 50 μm to 3 mm in length) compared to the diameter of the carrier nanofibers (nanometers). The new hybrid structure preserved the fibrous morphology of the polymer phases up to 250°C. The overall morphology of the hybrid composite was tunable by changing the fractions of the two polymeric phases. The particle‐polymer hybrid structures created morphologies that might find applications in various areas such as the interlayer toughening of laminated composites. It was shown that m‐phase/MCF@x‐phase nonwoven integrated into epoxy matrix composite laminates as interlayer, increased the strain at failure and ultimate strength under tensile loading by 11% and 9%, respectively.

Lotus Leaf-Inspired Breathable Membrane with Structured Microbeads and Nanofibers.

Electrospinning is a feasible technology to fabricate nanomaterials. However, the preparation of nanomaterials with controllable structures of microbeads and fine nanofibers is still a challenge, which hinders widespread applications of electrospun products. Herein, inspired by the micro/nanostructures of lotus leaves, we constructed a structured electrospun membrane with excellent comprehensive properties. First, micro/nanostructures of membranes with adjustable microbeads and nanofibers were fabricated on a large scale and quantitatively analyzed based on the controlling preparation, and their performances were systematically evaluated. The deformation of diverse polymeric solution droplets in the electrospinning process under varying electric fields was then simulated by molecular dynamic simulation. Finally, novel fibrous membranes with structured sublayers and controllable morphologies were designed, prepared, and compared. The achieved structured membranes demonstrate a high water vapor transmission rate (WVTR) > 17.5 kg/(m2 day), a good air permeability (AP) > 5 mL/s, a high water contact angle (WCA) up to 151°, and a high hydrostatic pressure of 623 mbar. The disclosed science and technology in this article can provide a feasible method to not only adjust micro/nanostructure fibers but also to design secondary multilayer structures. This research is believed to assist in promoting the diversified development of advanced fibrous membranes and intelligent protection.

Facile generation of crumpled polymer strips by immersion electrospinning for oil spill cleanups

The fabrication of electrospun products with desired structures and improved oil sorption capacities has attracted increasing attention in recent years; however, the overall geometry of electrospun products has rarely been investigated. Herein, we report a promising and competitive strategy for the preparation of novel electrospun polystyrene (PS) strips with advanced crumpled geometries for oil spill cleanups. The crumpled PS strips were prepared by immersion electrospinning, in which the nozzle and collector were simultaneously immersed in a coagulation bath. By controlling the processing parameters such as applied voltage and polymer concentration, the geometric morphology of the crumpled strips was precisely regulated. Benefiting from the crumpled structure, the crumpled strips demonstrated oil sorption capacities of approximately 83, 77, and 72 g/g for silicone, canola, and mineral oils, respectively. These values significantly higher than the values exhibited by the straight conventional electrospun fibers. The reported strategy offers a novel perspective on the rational design of electrospun products for oil sorption applications.

Hyaluronic acid/lactose-modified chitosan electrospun wound dressings – Crosslinking and stability criticalities

Polysaccharide electrospun wound dressings should be an effective strategy in the field of wound care, as they combine an extracellular matrix-like structure with excellent biomimicry. However, their high hydrophilicity and large surface area cause a rapid dissolution in aqueous environments, compromising their clinical employment. In the present paper, electrospun membranes prepared using hyaluronic acid, a bioactive lactose-modified chitosan (CTL), and polyethylene oxide have been crosslinked using glutaraldehyde, genipin, EDC/NHS or thermal treatments, obtaining very poor results in terms of membrane stability. Therefore, carbonyldiimidazole (CDI) and methacrylic anhydride were investigated in an innovative way, where CDI proved to be the best compromise between nanofiber water resistance, architecture maintenance and degradability. Indeed, the swelling and degradation behavior as well as the water vapor permeability of these matrices were tested, revealing the effectiveness of the electrospun products in absorbing large amount of liquid while maintaining the balance between water retention and gas permeability.

PVP/Highly Dispersed AgNPs Nanofibers Using Ultrasonic-Assisted Electrospinning.

Silver nanoparticles (AgNPs) are novel materials with antibacterial, antifungal, and antiviral activities over a wide range. This study aimed to prepare polyvinylpyrrolidone (PVP) electrospinning composites with uniformly distributed AgNPs. In this study, starch-capped ~2 nm primary AgNPs were first synthesized using Atmospheric pressure Pulsed Discharge Plasma (APDP) at AC 10 kV and 10 kHz. Then, 0.6 wt.% AgNPs were mixed into a 10 wt.% PVP ethanol-based polymer solution and coiled through an Ultrasonic-assisted Electrospinning device (US-ES) with a 50 W and 50 kHz ultrasonic generator. At 12 kV and a distance of 10 cm, this work successfully fabricated AgNPs-PVP electrospun fibers. The electrospun products were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High-Resolution TEM (HR-TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermogravimetric (TG), and X-ray Photoelectron Spectroscopy (XPS) methods.

Combination of 3D Printing and Electrospinning Techniques for Biofabrication

AbstractThis review presents the different combination methods of 3D printing and electrospinning processes and discusses the advantages of each method. Also, the applications of products of the hybrid process in the biomedical field, including tissue engineering and regenerative medicine, are thoroughly discussed. 3D printing and electrospinning are separate approaches for generating structured materials in a variety of biomedical applications. However, some shortfalls, such as the low resolution of 3D printing and uncontrollable shape of electrospun products, limits their application performances. Therefore, new ideas that combine 3D printing and electrospinning methods are proposed to give full play to their strengths and mitigate their weaknesses, which provide an effective and powerful platform for fabricating novel structural materials. Finally, a future vision regarding challenges and perspectives in the combination of 3D printing and electrospinning techniques is proposed.

Oriented ZnO nanoflowers obtained after calcination of electrospinning poly(vinyl alcohol)/zinc oxide/zinc acetate composite mats

Recently, nanofibers have attracted attention from researchers worldwide because they can be applied in various fields. The obtaining of oriented ZnO nanoflowers from polyvinyl alcohol (PVA) at a concentration of 10 wt% loaded with ZnO nanoparticles and zinc acetate (Zn(OAc)2) at various concentrations by electrospinning was investigated. The molecular weight of PVA was determined to be approximately 63,547 g/mol. The effects of the Zn(OAc)2 concentration on the electrical conductivity of the polymer suspension and the morphological properties of the composite nanofibers were also determined. The electrical conductivity increased with increasing Zn(OAc)2 concentration as a consequence of greater availability of charge. Also, this is likely because the accumulation of particles might increase the charge, which would result in an increase in the average fiber diameter of the obtained electrospun product. Finally, FT-IR spectra indicated that ZnO and Zn(OAc)2 were merely suspended in the aqueous PVA solution without any chemical bonding of ZnO and Zn(OAc)2 with the PVA chains. They also indicated that PVA could be composed entirely of nanofibers and, simultaneously, Zn(OAc)2 could be converted to ZnO after calcination at 600 °C.