Needleless Electrospinning Technique Research Articles

Carbon Fibers Doped by Binary Phosphides as an Electrocatalytic Layer for PEM Electrolysers

Hydrogen evolution reactions (HER) are important in a variety of electrochemical devices, such as electrolysers and fuel cells. To reduce the reaction overpotential and reduce energy consumption, efficient, low-cost, and durable electrocatalysts must be developed. Needle-less electrospinning (NLE) technique was used to prepare the fibrous electrocatalyst. NLE is a user-friendly and adaptable technique for large-scale low-cost fiber production. NLE created transition metal phosphides carbon fibers (TMP CF). The precursor foam was folded between two Al 2 O 3 ceramic plates. The heat treatment was carried out in a tube furnace at 1200 °C in an Ar atmosphere, followed by a reduction in an H 2 atmosphere at 780 °C. The electrolyser's membrane electrode assembly can be immediately submerged in the final TMP CF in the form of plates. The created NiCoP catalytic plates could be directly used in electrolyser's membrane electrode assembly of PEM electrolysers. In a three-electrode system, the electrochemical activity of the produced electrocatalysts was evaluated using linear sweep voltammetry. The electrochemical activity of the produced electrocatalysts were evaluated using linear sweep voltammetry. The catalyst's stability and endurance in acidic and alkaline environments were investigated.

Antibacterial biodegradable nanofibrous membranes by hybrid needleless electrospinning for high-efficiency particulate matter removal

Particulate matters (PMs) seriously threaten people’s health. Nanofibrous filters exhibit the great potential to stop PMs from being breathed into the respiratory system. Here, cellulose acetate/quaternary chitosan (CA/Q-CS) composite nanofibrous membranes were fabricated via a novel hybrid needleless electrospinning technique. The first layer of the CA nanofibrous membrane was generated as the supporting part by a rotary cylinder spinneret, while the second layer of the Q-CS nanofibrous membrane was fabricated via a rotary coil spinneret. The aggregate structure transition from 2D to 3D could be regulated by controlling the repulsive gap between two spinnerets. The CA/Q-CS composite nanofibrous air filter has a high filtration efficiency (96.4% for PM0.3, 99.9% for PM1.0, and 100% for PM2.5), and low air resistance (48 Pa). Meanwhile, these nanofibrous air filters exhibit excellent biodegradability in various environments and high antibacterial performance (98.27 ± 0.45% for E. coli, 98.65 ± 0.26% for S. aureus). This work provides a novel thought for the industrial production of biodegradable and antibacterial nanofibrous high-performance air filters.

An ultrasound-enhanced electrospinning for generating multilayered nanofibrous structures

The ability to modify nanofiber diameter on the fly can give an opportunity to create advanced nanofiber materials with complex design. Such flexibility provides possibilities to produce materials with gradient structures (physical and mechanical), desirable in wound healing and tissue engineering applications. We investigated a needleless ultrasound-enhanced electrospinning technique (USES) for generating multilayered nanofiber mats. The aim was to gain understanding of how the process parameters of USES affect the thickness and morphology of nanofibers. Levels of three process parameters were changed in a stepwise manner, permitting us to create multiple layers of nanofibers with different thickness. In the first test we found that by increasing the ultrasound burst rate from 150 Hz to 1800 Hz, the average nanofiber diameter increased by 90 nm. The second test showed a 170 nm decrease in average fiber diameter when ultrasound burst count was increased from 1200 Hz to 10000 Hz. The third set of experiments showed a minimal increase in fiber diameter when the duty cycle was decreased from 11.5% to 1.8%. Fourier transform infrared spectroscopy revealed no process induced transformations when generating nanofibers from aqueous PEO solutions with the USES device. In conclusion, USES enables us to modify nanofiber thickness in real time, and consequently, to generate multiple fiber layers having different average fiber diameter. Therefore, we believe that USES as a novel needleless electrospinning method holds promise for manufacturing of multilayered (gradient) nanofiber structures for wound healing and tissue engineering applications.

Fabrication of Polyvinylpyrrolidone (PVP) Nanofibrous Membranes using Mushroom-Spinneret Needleless Electrospinning

Mushroom-spinneret is an improved spinneret design for needleless electrospinning apparatus, which has a bowl-shaped base with a mushroom-shaped cover. The mushroom spinneret can overcome some limitations that is often associated with the needleless electrospinning technique, i.e., high excitation voltages, poor stability of free liquid, and difficulty of controlling the spatial motion of multiple jets. In this study, we fabricate polyvinylpyrrolidone (PVP) nanofibrous membranes using mushroom-spinneret needleless electrospinning and determine the effect of solution concentration and applied voltage on the fiber morphology and diameter. The solution concentration had significant effect on the fibers diameter. When the solution concentration was increased from 8 wt% to 12 wt%, the average fibers diameter increased from 0.99 μm to 1.31 μm and the fibers diameter distribution became wider. Moreover, the average fiber diameter decreased from 1.31 μm to 1.16 μm when the applied voltage was increased from 30 kV to 45 kV. The coefficient of variations (CV) for all membrane samples ranged from 0.12 - 0.26, indicated uniform fibers.

Fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate and gelatin developed using needleless electrospinning

Spirulina is a microalga that is well-known for its high protein content and biological activities directly related to its antioxidant capacity. The objective of this study was to produce fast-dissolving antioxidant nanofibers based on Spirulina protein concentrate (SPC) and gelatin using needleless electrospinning technique. The effect of mixing ratios of SPC (10% w/w) and gelatin (20% w/w) on the viscosity, electrical conductivity and surface tension of electrospinning solutions as well as diameter and morphology of resulting nanofibers was investigated. Increasing the SPC level in the solution blends resulted in a decrease in apparent viscosity and electrical conductivity and an almost stable trend in surface tension (29.25–32.19 mN/m) that led to diminish of diameter of the nanofibers. Scanning electron microscopy images showed that SPC/gelatin ratio of 40:60 led to the production of uniform and bead-free nanofibers with a relatively smaller average diameter (208.7 ± 46.5 nm). Atomic force microscopy images indicated mesh-like, fibrillary, and bead-free structures. Fourier transform infrared spectroscopy verified the formation of composite nanofibers and intermolecular interactions between both proteins. X-ray diffraction and thermal analysis showed higher amorphous structure and stability of produced SPC/gelatin nanofibers in comparison to pure materials which was favorable for formation of stable fast-dissolving fibers. Results of DPPH and ABTS radical scavenging activities showed that the antioxidant activity of composite nanofibers significantly improved with increasing SPC mixing ratio (p < 0.05). The dissolution test demonstrated that SPC/gelatin nanofibers can be rapidly dissolved in aqueous medium within 2 s. Finally, the results indicated that the electrospun SPC/gelatin nanofibers could be potentially used for nutraceutical delivery in food and packaging applications under high humidity.

Optimization of Nylon 6 electrospun nanofiber diameter in needle-less wire electrode using central composite design and response surface methodology

In this study, Nylon 6 nanofiber were prepared by needle-less wire electrospinning technique. Since, the fiber diameter determines the porosity, filtration efficiency, and mechanical properties of electrospun nanofiber mat, Central Composite Design (CCD) and Response Surface Methodology have been employed to design the experiments and evaluate the interactive effects of the operating variables such as concentration of the polymeric solution, the distance between two electrodes, applied voltage, and relative humidity (RH%) on the diameter of the Nylon 6 nanofiber. With this connection, an objective of this study was to find out the most influential variables for the finest nanofiber diameter during the spinning with wire type electrode to make the highest possible effective face mask without the addition of any functional additives in it. The overall results show that the combined effect of 12% polymer concentration, 65% RH, 155 mm distance between two electrodes, and 40 kV applied positive voltage have the strongest surface response and are the most significant than the other interactive effects. The Pareto chart illustrates the order of significance affecting the Nylon 6 nanofiber diameter in the order of concentration of the polymeric solution, RH%, the distance between electrodes, and applied positive voltage. Further, bacterial filtration efficiency% of the control sample and five-layer facemask incorporated with optimized nanofiber membrane was found to be 87.4% and 97.5%, respectively, against Staphylococcus Aureus ATCC 6538 bacteria.

Effect of heat treatment on the morphology of carbon fibers doped with Co2p nanoparticles

Carbon fibers (CFs) decorated by Co2P nanoparticles and carbon nanotubes were prepared via needle-less electrospinning technique. Formation of catalytically active Co2P nanoparticles and growth of carbon nanotubes were monitored in open and closed sintering environment at different sintering exposure times. Higher porosity, important in the catalytic reaction for easier penetration of electrolyte into the CFs, was achieved by mixing two immiscible polymers with natrium dodecyl sulfate and subsequent heat treatment process. Structure and morphology of the prepared modified carbon fibers were characterized by XRD, SEM and TEM. The time of heat exposure at the sintering temperature of 1200 °C and closure of the sintering space showed distinct effect on the growth and shape of carbon nanotubes. SEM and Raman spectroscopy revealed that closure of the system led to the formation of carbon nanotubes with smaller diameters and less structural disorder. Comparing of as-prepared CFs revealed that CFs with Co2P sintered in the closed system exhibited the best electrocatalytic activity for hydrogen evolution reaction due to lower overpotential and smaller Tafel slope in acidic solution.Graphic abstract

Chelidoniummajus L. Incorporated Emulsion Electrospun PCL/PVA_PEC Nanofibrous Meshes for Antibacterial Wound Dressing Applications.

Presently, there are many different types of wound dressings available on the market. Nonetheless, there is still a great interest to improve the performance and efficiency of these materials. Concerning that, new dressing materials containing natural products, such as medicinal plants that protect the wound from infections but also enhance skin regeneration have been or are being developed. Herein, we used for the first time a needleless emulsion electrospinning technique for incorporating Chelidonium majus L. (C. majus), a medicinal plant widely known for its traditional therapeutic properties, in Polycaprolactone (PCL)/Polyvinyl Alcohol (PVA)_Pectin (PEC) nanofibrous meshes. Moreover, the potential use of these electrospun nanofibers as a carrier for C. majus was also explored. The results obtained revealed that the produced PCL/PVA_PEC nanofibrous meshes containing C. majus extract displayed morphological characteristics similar to the natural extracellular matrix of the skin (ECM). Furthermore, the produced meshes showed beneficial properties to support the healing process. Additionally, the C. majus-loaded PCL/PVA_PEC nanofibrous meshes inhibited Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth, reaching a 3.82 Log reduction, and showed to be useful for controlled release, without causing any cytotoxic effect on the normal human dermal fibroblasts (NHDF) cells. Hence, these findings suggest the promising suitability of this novel wound dressing material for prevention and treatment of bacterial wound infections.

The Effect of the Controlled Release of Platelet Lysate from PVA Nanomats on Keratinocytes, Endothelial Cells and Fibroblasts.

Platelet lysate (PL) provides a natural source of growth factors and other bioactive molecules, and the local controlled release of these bioactive PL components is capable of improving the healing of chronic wounds. Therefore, we prepared composite nanofibrous meshes via the needleless electrospinning technique using poly(vinyl alcohol) (PVA) with a high molecular weight and with a high degree of hydrolysis with the incorporated PL (10% w/w). The morphology, wettability and protein release from the nanofibers was then assessed from the resulting composite PVA–PL nanomats. The bioactivity of the PVA–PL nanomats was proved in vitro using HaCaT keratinocytes, human saphenous endothelial cells (HSVECs) and 3T3 fibroblasts. The PVA–PL supported cell adhesion, proliferation, and viability. The improved phenotypic maturation of the HaCaT cells due to the PVA–PL was manifested via the formation of intermediate filaments positive for cytokeratin 10. The PVA–PL enhanced both the synthesis of the von Willebrand factor via HSVECs and HSVECs chemotaxis through membranes with 8 µm-sized pores. These results indicated the favorable effects of the PVA–PL nanomats on the three cell types involved in the wound healing process, and established PVA–PL nanomats as a promising candidate for further evaluation with respect to in vivo experiments.

Synthesis and characterization of WS2/SiO2 microfibers

Tungsten disulfide polycrystalline microfibers were successfully synthesized by a process involving electrospinning, calcination, and sulfidation steps. We used an aqueous solution of silicotungstic acid (H4SiW12O40) and polyvinyl alcohol as precursors for the synthesis of composite fibers by the needle-less electrospinning technique. The obtained green composite fibers (av. diam. 460 nm) were converted by calcination in air to tungsten oxide WO3 fibers with traces of SiO2 and a smaller diameter (av. diam. 335 nm). The heat treatment of the WO3 fibers under flowing H2/H2S/N2 stream led to conversion to tungsten disulfide WS2 with retention of the fibrous morphology (av. diam. 196 nm). Characterization of the intermediate and final fibers was performed by the XRD, SEM, TEM, HAADF STEM EDS, elemental analyses ICP-OES, and IR spectroscopy methods.

Investigation of metallic nanoparticle distribution in PAN/magnetic nanocomposites fabricated with needleless electrospinning technique

Needleless electrospinning can be used to produce polyacrylonitrile nanofibres, for example, to which magnetic nanoparticles can additionally be added. Such composite nanofibres can then be stabilised and carbonised to produce carbon composite nanofibres. The magnetic nanoparticles have an influence not only on the structure but also on the mechanical and electrical properties of the finished carbon nanofibres, as does the heat treatment during stabilisation and incipient carbonisationThe present study reports on the fabrication, heat treatment and resulting properties of poly(acrylonitrile) (PAN)/magnetic nanofibre mats prepared by needleless electrospinning from polymer solutions. A variety of microscopic and thermal characterisation methods were used to investigate in detail the chemical and morphological transition during oxidative stabilisation (280 °C) and incipient carbonisation (500 °C). PAN and nanoparticles were analysed during all stages of heat treatment. Compared to pure PAN nanofibres, the PAN/ magnetic nanofibers showed larger fiber diameters and the presence of beads and agglomerations. In this study, magnetic nanofibers were investigated in more detail with the aim of detecting undesired agglomerations. Visual observation, for example with CLSM or SEM, does not provide conclusive evidence of agglomerations in the nanofibers. But based on the capabilities of SEM/EDS many different types of samples can be easily analysed where other analytical techniques simply cannot give the fast answer.

Dissymmetric interface design of SnO2/TiO2 side-by-side bi-component nanofibers as photoanodes for dye sensitized solar cells: Facilitated electron transport and enhanced carrier separation

SnO2/TiO2 type II heterojunctions are often introduced to enhance the separation efficiency of photogenerated carriers in photoelectrochemical electrodes, while most of these heterojunctions are of core–shell structure, which often limits the synergistic effect from the two components. In this work, dissymmetric SnO2/TiO2 side-by-side bi-component nanofibers (SBNFs) with tunable composition ratios have been prepared by a novel needleless electrospinning technique with two V-shape connected conductive channels (V-channel electrospinning). Results show that this V-channel electrospinning technique is more stable, controllable and tunable for the large-scale preparation of SBNF materials compared to the traditional electrospinning using two side-by-side metal needles. And these SnO2/TiO2 SBNFs are dissymmetric and comprised of a tiny SnO2 NF (tunable diameter within 20–80 nm) and a Sn-doped TiO2 NF (diameter of ~ 250 nm) with a side-by-side structure. Moreover, the dye-sensitized solar cells (DSSCs) based these dissymmetric SnO2/TiO2 SBNFs show the maximum power conversion efficiency (PCE) of 8.3%, which is 2.59 times that of the ones based on the TiO2 NFs. Series of analyses indicate that the enhancements in PCE could mainly be due to the improved electron transport via SnO2 NFs and the enhanced carrier separation via dissymmetric SnO2/TiO2 heterojunction interface. This research will give some new insight in the preparation of SBNFs for high-performance photoelectrochemical devices.

Cytocompatibility of Bilayer Scaffolds Electrospun from Chitosan/Alginate-Chitin Nanowhiskers.

In this work, a bilayer chitosan/sodium alginate scaffold was prepared via a needleless electrospinning technique. The layer of sodium alginate was electrospun over the layer of chitosan. The introduction of partially deacetylated chitin nanowhiskers (CNW) stabilized the electrospinning and increased the spinnability of the sodium alginate solution. A CNW concentration of 7.5% provided optimal solution viscosity and structurization due to electrostatic interactions and the formation of a polyelectrolyte complex. This allowed electrospinning of defectless alginate nanofibers with an average diameter of 200–300 nm. The overall porosity of the bilayer scaffold was slightly lower than that of a chitosan monolayer, while the average pore size of up to 2 μm was larger for the bilayer scaffold. This high porosity promoted mesenchymal stem cell proliferation. The cells formed spherical colonies on the chitosan nanofibers, but formed flatter colonies and monolayers on alginate nanofibers. The fabricated chitosan/sodium alginate bilayer material was deemed promising for tissue engineering applications.

Impact of Various Sterilization and Disinfection Techniques on Electrospun Poly-ε-caprolactone.

Electrospun materials made from biodegradable polycaprolactone are used widely in various tissue engineering and regenerative medicine applications because of their morphological similarity to the extracellular matrix. However, the main prerequisite for the use of such materials in clinical practice consists of the selection of the appropriate sterilization technique. This study is devoted to the study of the impact of traditional sterilization and disinfection methods on a nanofibrous polycaprolactone layer constructed by means of the needleless electrospinning technique. It was determined that hydrogen peroxide plasma treatment led to the loss of fibrous morphology and the creation of a foil. However, certain sterilization (ethylene oxide, gamma irradiation, and peracetic acid) and disinfection techniques (ethanol and UV irradiation) were found not to lead to a change in morphology; thus, the study investigates their impact on thermal properties, molecular weight, and interactions with a fibroblast cell line. It was determined that the surface properties that guide cell adhesion and proliferation were affected more than the bulk properties. The highest proliferation rate of fibroblasts seeded on nanofibrous scaffolds was observed with respect to gamma-irradiated polycaprolactone, while the lowest proliferation rate was observed following ethylene oxide sterilization.

Sound Absorption of Sustainable Polymer Nanofibrous Thin Membranes Bonded to a Bulk Porous Material

In this paper, the standardized characterization of nanofibrous membranes used to coat three porous bulk acoustical materials (melamine foam, a polyester textile, and an MDF perforated panel) is presented. The membranes were manufactured from recyclable Polyamide 6 (PA6) and water-soluble polyvinyl alcohol (PVA) using the needleless electrospinning technique. This resulted in very thin membranes that had high porosity and very high airflow resistivity. The membranes were collected in a high-permeability nonwoven substrate. Measured results in both an impedance tube and a reverberation room showed significant improvements in the sound absorption performance of the bulk materials after incorporating the nanofibrous layer. The application of the membranes on the surface of a traditional air-backed perforated panel also improved the sound absorption, exhibiting a broad peak of sound absorption in the low-frequency range. This was particularly true when the membrane area weight was increased. It is concluded that these materials, manufactured as described in this paper, can be alternatives to glass, mineral, and ceramic fibrous materials, which have high carbon footprints.

The assessment of electrospun scaffolds fabricated from polycaprolactone with the addition of L-arginine

Polycaprolactone (PCL) was electrospun with the addition of arginine (Arg), an α-amino acid that accelerates the healing process. The efficient needleless electrospinning technique was used for the fabrication of the nanofibrous layers. The materials produced consisted mainly of fibers with diameters of between 200 and 400 nm. Moreover, both microfibers and beads were present within the layers. Higher bead sizes were observed with the increased addition of arginine. The arginine content within the layers as well as the weight of the resultant electrospun materials were enhanced with the increased addition of arginine to the electrospinning solution (1, 5 and 10 wt%). The PCL + 1% Arg nanofibrous layer contained 5.67 ± 0.04% of arginine, the PCL + 5% Arg layer 22.66 ± 0.24% of arginine and the PCL + 10% Arg layer 37.33 ± 0.39% of arginine according to the results of the elemental analysis. A high burst release within 5 h of soaking was recorded for the PCL + 5% and PCL + 10% nanofibrous layers. However, the release rate of arginine from the PCL + 1% Arg was significantly slower, reaching a maximum level after 72 h of soaking. The resulting materials were hydrophobic. Hemocompatibility testing under static conditions revealed no effect on hemolysis following the addition of arginine and the prolongation of the prothrombin time with the increased addition of arginine, thus exerting an influence on the extrinsic and common pathway of coagulation activation. The results of the dynamic hemocompatibility assessment revealed that the numbers of blood cells and platelets were not affected significantly by the various electrospun samples during incubation. The TAT, β-thromboglobulin and SC5-b9 concentrations were characterized by a moderate increase in the PCL group compared to those of the control group. The presence of arginine resulted in a decrease in the investigated hemocompatibility markers. The PMN elastase levels were comparable with respect to all the groups.

Needleless electrospinning of poly(acrylic acid) superabsorbent: Fabrication, characterization and swelling behavior

In this work, nanofibrous hydrogel has been fabricated from needleless electrospinning of Poly(acrylic acid) (PAA) in an aqueous solution with different concentrations. First, all solution samples were characterized for pH, surface tension, conductivity and viscosity. Next, electrospinnability of the PAA-water dope solution was investigated using the needleless electrospinning technique under constant conditions. Results indicated that the PAA-water solution was not electrospinnable. Therefore, the neutralization of carboxylic groups in the PAA chemical structure using the NaOH solution was investigated to enhance the PAA electrospinnability. Morphology observation revealed that the fiber diameters ranged from 40 to 250 nm and increased with increasing the solution concentrations. Increasing the neutralization degree (10%, 15% and 20% with 50 wt% NaOH solution) led to increase the dope viscosity and conductivity. The resultant nanofibers could be rendered water-insoluble by incorporating 1,4-butanediol diglycidyl-ether in the PAA-water dope solution, then heat-induced crosslinking was performed using a microwave at different curing times (1–5 min) and temperatures (45–105 °C). The nanofibrous hydrogel mat was then characterized by FTIR. The resulting nanofibrous hydrogel showed remarkable water absorption capacity up to 17,000% and 51,000% (within 15 min) in the standard saline solution and distilled water, respectively.

Critical condition of electrohydrodynamic jetting from a polymer-solution droplet on a conductive wire

An experimental study was conducted to determine the threshold electrostatic field to initiate electrohydrodynamic jetting from a polymer solution droplet wetting on a conductive wire. The study is crucial to understand the roles of the material and process parameters in wire-based needleless electrospinning for controllable mass production of continuous nanofibers. Two types of polymer solutions, i.e., polyacrylonitrile/N,N-dimethylformamide (PAN/DMF) and aqueous polyethyloxide solution (PEO/H2O), with the mass concentrations of 4%, 8%, 12%, and 16% for PAN and 1%, 2%, 4%, 6%, and 8% for PEO, respectively, were considered in the experiments. Taut thin copper wires with diameters of 0.254, 0.508, 1.016, and 1.524 mm (i.e., 0.01, 0.02, 0.04, and 0.06 in.) were utilized, respectively, as the positive electrodes. The effects of the polymer concentration and wire diameter on the threshold electrical voltage for jetting initiation and nanofiber diameter were examined. Given the droplet volume and spacing between the copper wire and fiber collector, experimental observations show that the threshold electrical voltage increases with increasing either polymer mass concentration or wire diameter. In addition, the effects of polymer mass concentration on the transient shear viscosity and surface tension of the PAN/DMF solutions were examined. It shows the positive correlation between the transient shear viscosity and polymer mass concentration, shear thinning of the polymer solution at a high shear rate, and nearly constant surface tension of the polymer solution in the range of the present PAN mass concentration. Furthermore, a simple electrostatic model is formulated to phenomenologically elucidate the experimental observations. The present study provides useful scaling laws for controllable scale-up nanofiber fabrication by means of a wire-based needleless electrospinning technique.

High Production Rate of High Purity, High Fidelity Nafion Nanofibers via Needleless Electrospinning

This study demonstrates the needleless electrospinning of Nafion nanofibers via foam electrospinning. Compared to needle electrospinning, a 2 orders of magnitude higher production rate (9729 vs 14 mg h–1 m–2) was obtained at similar fidelity (233 ± 62 vs 216 ± 69 nm fiber diameters). Additionally, needleless electrospinning produced defect-free high purity Nafion nanofibers (98 wt % Nafion) compared to no fibers (beads) using needle electrospinning at a similar polymer solution concentration. Furthermore, the Young’s modulus and proton conductivity of the fiber mats produced by needleless electrospinning (42.6 MPa and 43.8 mS cm–1, respectively) were higher than those produced by needle electrospinning (20.9 MPa and 18.0 mS cm–1, respectively). Therefore, high fidelity, high purity Nafion nanofibers at higher production rates with improved mechanical properties and proton conductivity were produced with this needleless electrospinning technique.

Synergistic Effect and Characterization of Graphene/Carbon Nanotubes/Polyvinyl Alcohol/Sodium Alginate Nanofibrous Membranes Formed Using Continuous Needleless Dynamic Linear Electrospinning.

In this study, a self-made continuous needleless dynamic linear electrospinning technique is employed to fabricate large-scale graphene (Gr)/carbon nanotubes (CNT)/polyvinyl alcohol (PVA)/sodium alginate (SA) nanofibrous membranes. The synergistic effect of Gr and CNT fillers in the PVA/SA membrane is explored in depth by changing the volume ratio (v/v) of Gr and CNT as 10:0, 8:2, 6:4, 4:6, 2:8, and 0:10. Microstructure, functional group, conductivity, and hydrophilicity of PVA/SA/Gr/CNT membranes was characterized. Results show that the linear electrode needleless electrospinning technique can be spun into 200-nm diameter fibers. The PVA/SA/Gr/CNT fibrous membrane has good hydrophilicity and thermal stability. A Gr/CN ratio of 6:4 possessed the optimal synergistic effect, which showed the lowest surface resistivity of 2.53 × 103 Ω/m2. This study will provide a reference for the large-scale preparation of nanofibrous membrane used as a artificial nerve conduit in the future.