Electrospinning Academic News

Effect of electrospinning on solution properties in tissue engineering 2021-03-17

Electrospinning, a technology capable of fabricating ultrafine fibers (microfibers and nanofibers), has been investigated by various research groups for the production of fibrous biopolymer membranes for potential medical applications. In this study, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), a natural, biocompatible, and biodegradable polymer, was successfully electrospun to form nonwoven fibrous mats. The effects of different electrospinning parameters (solution feeding rate, applied voltage, working distance and needle size) and polymer solution properties (concentration, viscosity and conductivity) on fiber diameter and morphology were systematically studied and causes for these effects are discussed. The formation of beaded fibers was investigated and the mechanism presented. It was shown that by varying electrospinning parameters within the processing window that was determined in this study, the diameter of electrospun PHBV fibers could be adjusted from a few hundred nanom

Electrospinning of multifunctional cellulose acetate membrane and its adsorption properties for ionic dyes 2021-03-17

Electrospinning of cellulose acetate with appropriated solvent system is the most straightforward method for fabricating micro- and nanofibers. To simultaneously and effectively remove both cationic and anionic dyes, a novel cost-effective multifunctional cellulose acetate (CA) fibers membrane was prepared by electrospinning followed by deacetylation, carboxymethylation and polydopamine (PDA) coating. The adsorption properties of PDA@DCA-COOH membrane were evaluated with methylene blue (MB) and Congo red (CR) as the ionic representatives for their removal. The results indicated that carboxyl, hydroxyl and amine multifunctional groups had been successfully grafted on the surface of the nanofibers with the maximum adsorption capacities of 69.89 and 67.31 mg g−1 for MB and CR, respectively, in the individual systems. The effect of co-existed dyes, inorganic salts and surfactants on the uptake of MB and CR in the simulated real complex system was strongly depended on the initial pH and ion

Sustained-release multiple-component cellulose acetate nanofibers fabricated using a modified coaxial electrospinning process 2021-03-17

Two drawbacks of the traditional electrospinning process when used for producing nanofibers for drug release are that clogging of the spinneret is often experienced, and the fibers produced often exhibit a tailing-off of drug release over sustained periods. The present study investigates the preparation of ferulic acid (FA) sustained-release cellulose acetate (CA) nanofibers, in which a third component, polyvinylpyrrolidone (PVP), was included into the nanocomposites for an improved sustained drug release profile. A modified coaxial electrospinning process, in which only organic solvent N,N-dimethylacetamide was used as a sheath fluid, was exploited for a smooth and continuous fabrication of multiple-component nanofibers. Under an applied voltage of 16 kV and an optimized sheath-to-core flow rate ratio of 0.11, three types of FA/PVP/CA composite nanofibers (with varied of PVP content) were generated. These nanofibers had higher quality in terms of size and distribution of nanofiber dia

Nanofiber‐Based Hydrocolloid from Colloid Electrospinning Toward Next Generation Wound Dressing 2021-03-17

Nanofiber‐based hydrocolloid scaffold is prepared by colloid electrospinning of thermoplastic polyurethane (TPU)/sodium carboxymethyl cellulose (S.CMC) in tetrahydrofuran (THF)/dimethylformamide (DMF). The most suitable process of electrospinning for successful formation of fibers is investigated by controlling the concentration of polymeric solution and co‐solvent ratio. In order to accomplish high wettability, the amount of colloid (S.CMC) and the co‐solvent ratio (THF/DMF), which affects the morphology of fibers, are adjusted. Finally, the open wound healing effect is confirmed using nanofiber‐hydrocolloid from in vivo animal studies. A detailed study of the wound healing process is also demonstrated for the first time.

Electroblowing and electrospinning of fibrous diclofenac sodium-cyclodextrin complex-based reconstitution injection 2021-03-17

Electrospinning, electroblowing and freeze-drying were investigated to prepare fast dissolving cyclodextrin-based drug-loaded solid complexes. Combining the huge surface area of fibrous mats with the capabilities of cyclodextrins to prepare a reconstitution injection was tested to overcome the instability of liquid-based products. Diclofenac sodium was used as drug with limited water solubility and 2-hydroxypropyl-β-cyclodextrin (HPβCD) as carrier and solubilizer. The applied composition of the complex was determined based on phase solubility measurements. In order to resolve the frequent unavoidable interruption of the fiber formation during electrospinning from the HPβCD solution, high-speed blowing air was coupled with the electrostatic force (electroblowing) to draw polymer-free HPβCD fibers steadily, moreover, at increased flow rates. According to the scanning electron microscopic images, X-ray diffraction, differential scanning calorimetry no traces of crystallinity of the drug w

Preparation and characterization of PVDF/Starch nanocomposite nanofibers using electrospinning method 2021-03-17

In this study, poly (vinylidene fluoride) PVDF/Starch nanofibers with a great potential for tissue engineering applications have been investigated. The electrospun nanofibers were formed by the electrospinning of the PVDF/Starch solutions in various ratios of PVDF to Starch. Characterizations of PVDF/Starch nanofiber were performed using rheometric mechanical spectroscopy (RMS), field emission scanning electron microscope (FE-SEM) and tensile test. The results showed that the addition of more Starch into the PVDF solution increased the viscosity of the prepared PVDF/Starch solutions. In addition, the mechanical properties of PVDF enhanced in the presence of Starch due to the higher mechanical properties of Starch chains. Also, addition of Starch into PVDF matrix increased the elongation at break from 58 to 8 mm.

In-situ growth of graphene on carbon nanofiber from lignin 2021-03-17

Design and synthesis of heterostructured carbon nanofibers is significant for applications in the field of optoelectronics, conductors and catalytic devices. Although lignin has been widely used as building blocks for fabricating nanofibers, it is still very challenging to synthesize conducting heterostructured carbon nanofibers without using additional catalysts. Herein, we first in-situ grew graphene grafted carbon nanofibers (G/CNFs) using calcium lignin sulfonate as starting materials without addition of catalysts. Through the electrospinning, pyrolysis and washing procedure, the as-spun nanofibers are converted into the flexible G/CNFs films. The in-situ formed CaS nanoparticles serve as catalysts for the growth of graphene on the surface of the CNFs, when the carbonization temperature is over 1100 °C. The as-prepared G/CNFs films exhibit superior electronic conductivity of 2377.9 S m−1, which is comparable to the values reported in the literature. As a proof-of-concept, the as-fa

Electrospinning technology was used to stabilize sodium ion storage 2021-03-17

Iron/manganese‐based layered transition metal oxides have risen to prominence as prospective cathodes for sodium‐ion batteries (SIBs) owing to their abundant resources and high theoretical specific capacities, yet they still suffer from rapid capacity fading. Herein, a dual‐strategy is developed to boost the Na‐storage performance of the Fe/Mn‐based layered oxide cathode by copper (Cu) doping and nanoengineering. The P2‐Na0.76Cu0.22Fe0.30Mn0.48O2 cathode material synthesized by electrospinning exhibits the pearl necklace‐like hierarchical nanostructures assembled by nanograins with sizes of 50–150 nm. The synergistic effects of Cu doping and nanotechnology enable high Na+ coefficients and low ionic migration energy barrier, as well as highly reversible structure evolution and Cu/Fe/Mn valence variation upon repeated sodium insertion/extraction; thus, the P2‐Na0.76Cu0.22Fe0.30Mn0.48O2 nano‐necklaces yield fabulous rate capability (125.4 mA h g−1 at 0.1 C with 56.5 mA h g−1 at 20 C) and

Electrochemical performance of electrospun lotus–root–structure porous multichannel carbon nanotubes for lithium–sulfur battery applications 2021-03-17

Lotus–root–structure porous multichannel carbon nanotubes with sidewalls are used in sulfur/carbon (P–MCNT) composites as a sulfur carrier for Li–sulfur (LiS) batteries. P–MCNT is prepared by a simple electrospinning method using coaxial needles, followed by heat treatment and etching. P–MCNT developed multichannel inner pores of different sizes in an axial direction when different amounts of polymethyl methacrylate (PMMA) were added. The sidewall–holes are prepared by adding SiO2 to the electrospinning solution followed by etching. As the porosity increases, the sulfur content reaches a maximum of 78 wt%. The sulfur/P–MCNT composite for LiS batteries exhibits superior performance with a high initial discharge capacity of 1315 mAh g−1 and maintained satisfactory cyclability. This superior performance was ascribed to the morphology of the P–MCNT, which both captured sulfur and restricted its loss during the charge–discharge process. In addition, the introduction of more pores into the c

Cobalt sulfide embedded carbon nanofibers as a self-supporting template to improve lithium ion battery performances 2021-03-17

Metal sulfides are getting increasing attention as cathodic materials in lithium-ion batteries due to their high theoretical capacities. However, the volume expansion and rapid decay of capacity are two main factors during charge and discharge that restricts the applicability of these electrodes. Herein, we reported a strategy to obtain cobalt sulfide (Co1-xS)-carbon nanofibers (CNFs) using an electrospinning technique combined with a solvothermal method to increase the capacity of cobalt sulfide and alleviate the volume expansion. Results showed that the as-obtained flexible self-supporting Co1-xS-CNFs electrode promotes the electron transfer and mechanical stability. Moreover, it was shown that Co1-xS was embedded in CNFs, which improved the electrical conductivity of the composite and alleviated the volume expansion caused by charging and discharging. The synergistic effect from the enhanced electrical conductivity of CNFs and high capacity of the Co1-xS exhibited a high specific di

Synthesis of PVDF/SiO2 nanofiber membrane using electrospinning method as a Li-ion battery separator 2021-03-17

This work reported synthesis of PVDF/SiO2 (Polyvinilidene fluoride/Silica) nanofiber membrane by electrospinning method that was used as a separator in li-ion battery. The effect of the SiO2 nanoparticle addition to the PVDF nanofiber membrane to improve membrane characteristics which include porosity, temperature stability, mechanical strength and the stability of battery capacity were systematically investigated. The electrospinning parameter was adjusted at a voltage of 15 kV, the flow rate of 1,5 ml/hour, the distance between needle to collector 17 cm and spinning time for 1 h. The immersion of PVDF membrane in colloid SiO2 nanoparticles was carried out for 1 h. Nanofiber membrane was characterized by SEM (Scanning Electron Microscope), n-butanol intrusion, the dimensional changes before and after heat treatment, stress–strain mechanical measurements with autograph and battery analyzer. The PVDF nanofiber membrane has a beaded fiber with an average fiber size was ∼656 nm. The nanop

Fabrication of high surface area ribbon electrodes for use in redox flow batteries via coaxial electrospinning 2021-03-17

A method for the preparation of electrospun with fibers possessing a ribbon-like cross-sectional shape was developed. These materials could prove beneficial as flow-through electrodes, since ribbons provide a higher surface-to-volume ratio compared to fibers, thereby providing higher reactive surface area at a given porosity. Fabrication of these materials was accomplished by electrospinning a coaxial fiber with a polystyrene core and polyacrylonitrile shell, followed by leaching of the core material leading to the collapse of the shell into a flat ribbon. The surviving shell was then carbonized to make an electrically conductive and electrochemically reactive fibrous structure. Analysis by x-ray computed tomography showed that ribbons of approximately 400 nm × 800 nm were produced, and experimental characterization revealed that they did indeed offer higher volumetric surface area than previously reported electrospun cylindrical fiber electrodes. The electrodes were characterized for

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