Electrospinning Academic News

Statistical analysis of nanofibers alignment in magnetic‐field‐assisted electrospinning including an alignment percentage formula 2021-03-18

Magnetic‐field‐assisted electrospinning (MFAES) is a simple and effective method to align polymer nanofibers. In this method, further research is needed to identify alignment mechanism. Hence, this article includes statistical analysis of affecting factors to investigate alignment mechanism in MFAES. Tip to target distance, magnets distance, voltage, and collection time, which are recognized as the most effective factors on nanofibers alignment, were applied in design of experiments. Central composite method was applied to get required experiments with designed expert 8 software. A response surface was proposed with regression coefficient of 97%. Then, the common physics concepts and statistical results were used to discuss the affecting mechanism of the electric and magnetic fields on the electrospinnig jet and the nanofibers alignment. Field emission scanning electron microscopy images were used to characterize the nanofibers alignment and calculate overall alignment percentage using

Electrospinning of chitosan/PVA nanofibrous membrane at ultralow solvent concentration 2021-03-18

In this work, chitin flakes were deacetylated with 50% (w/v) sodium hydroxide under nitrogen atmosphere at 120 °C for 80 min to obtain chitosan. The chitosan produced was characterized for degree of deacetylation (DD) and molecular weight. Chitosan with the DD of 78–80% was reproducibly obtained. Molecular weight showed an inverse relationship with concentration of NaOH. Chitosan nanofibrous membrane was prepared via the electrospinning of chitosan/ polyvinyl alcohol (CH/PVA) aqueous solutions with varying blend compositions. The characteristics of CH/PVA nanofibrous membranes were studied as a function of viscosity of solution and applied voltage. A uniform nanofibrous membrane of average fibre diameter of 80–300 nm was obtained with blend of 2% (w/v) chitosan solution in 1% (v/v) acetic acid and 5% (w/v) PVA in distilled water in the electric field of 20–25 kV with varying proportion of CH/PVA. With the CH/PVA mass ratios; 40/60 to 10/90, electrospinning of nanofibres could be done.

Electrospinning of Octenylsuccinylated Starch-Pullulan Nanofibers from Aqueous Dispersions 2021-03-18

We aimed to develop a greener process for dry-electrospinning food-grade modified starch through the elimination of organic solvents. The rheological properties and electrospinnability of aqueous dispersions of commercial octenylsuccinylated (OS) starches with various molecular weight (Mw) were investigated, yet only nanofibers with beads or defects could be obtained from OS starch with the highest Mw, i.e., Purity Gum@ Ultra (PGU). Further improvement in the fiber morphology was achieved by adding pullulan (PUL) as a minor component in the spinning dope. Smooth, continuous, and bead-free nanofibers (147-250 nm) were obtained from the PGU-PUL dispersions. Shown on an electrospinnability map, the successful electrospinning of 12%, 15%, and 20% (w/v) aqueous PGU dispersions required a minimum addition of 6%, 5%, and 3% (w/v) of PUL, respectively. The addition of PUL contributed to establishing sufficient molecular entanglement for electrospinning. This study provides a promising green pr

Photocatalytic properties of Fe2O3-modified rutile TiO2 nanofibers formed by electrospinning technique 2021-03-18

In this study, we aimed to fabricate rutile phase titania nano-catalysts by electrospinning and further doped them with different concentrations of ferric oxide by precipitation technique. The X-Ray Diffraction, Scanning Electron Microcopy and Energy-dispersive X-ray spectroscopy results of 4wt% ferric oxide modified titania nanofibers suggested that the doping of iron with titania nanofibers was highly achievable. It was observed, that ferric oxide is soluble in its lattice matrix, which provided be the rate determining step for degradation model dye i.e., Congo Red. The results confirmed that titania nanofibers incorporated ferric oxide presents the highest dye degradation efficiency and rate constant values, as compared to those of commercially available titanium nanoparticles and pristine nanofibers.

Substitution of petroleum-based polymeric materials used in the electrospinning process with nanocellulose: A review and future outlook 2021-03-18

The most fibrous reinforcing materials for engineered composites (e.g. carbon fiber, glass fiber) are solid fibers or loops, garments, and their preforms. In design and fabrication methods, the fiber orientation and design can therefore be regulated broadly. The continuous fibers from biobased materials such as plants are nevertheless growing interest. Nanocelluloses, which are projected to be cheaper than many other nanomaterials and potentially produce in great quantities, are of particular interest recently. They have an impressive strength to weight ratio and have so far demonstrated no care in their unmodified condition with respect to the climate, health and safety. The efficient and effective use of nanocellulose in continuous fibers is, however, difficult and a range of approaches have been studied where either directly or in combination with the polymers spin nanocellulose dispersions. In this study, a variety of approaches are reviewed and a perspective is provided to better

Randomly oriented and aligned cellulose fibres reinforced with cellulose nanowhiskers, prepared by electrospinning 2021-03-18

The goal of this work was to prepare random and aligned cellulose fibres by electrospinning. Cellulose acetate (CA) was used as a matrix and a mixture of acetic acid and acetone (1∶1) was used as an solvent. Cellulose nanowhiskers (CNWs) with different concentrations (0–5 wt‐%) were used as reinforcement. Microscopy studies showed fibres with smooth surfaces, different morphologies and diameters ranging between 200 and 3300 nm. It was found that the fibre diameters decreased with increased CNW contents. The microscopy studies also indicated well aligned fibres. Results from dynamic mechanical thermal analysis indicated improved mechanical properties with the addition of CNWs. The storage modulus of electrospun CA fibres increased from 81 to 825 MPa for fibres with 1 wt‐% CNW at room temperature. X‐ray analysis showed that the electrospun CA fibres had a crystalline nature and that there was no significant change in crystallinity with the addition of CNWs.

Alumina castable with electrospun fibers 2021-03-18

In this work, cement-free alumina castables with different fiber additives were produced. The effect of commercial polypropylene fibers was compared to that of magnesium borate precursor fibers produced by electrospinning. The drying behavior of different batches was monitored by means of thermogravimetry. Elastic moduli were estimated in dried, sintered and thermally-shocked samples through the impulse excitation technique. The mechanical strength as cold modulus of rupture (CMOR) was measured by three-point bending tests. The open porosity and bulk density after sintering were assessed by water immersion. The thermal shock resistance was evaluated by heating the samples up to 950 ∘C and then quenching with compressed air. After 1 or 5 thermal shock cycles, the residual CMOR was determined. The microstructure of fracture surfaces was analyzed by scanning electron microscopy (SEM). The possible formation of new phases during thermal treatment was also assessed by means of XRD. Finally,

Fabrication of PMMA/zeolite nanofibrous membrane through electrospinning and its adsorption behavior 2021-03-17

The present work investigates the effect of various solution parameters and electrospinning parameters on the characteristics of electrospun nanofibrous membranes. Scanning electron microscopy was used to analyze the surface morphology of the nanofibrous membrane. Adsorption test on methyl orange was also carried out and analyzed using the UV–vis. Results showed that increasing voltage decreased mean nanofiber diameter. Meanwhile, increasing PMMA concentration, feed rate, distance between collector‐and‐needle tip increased mean nanofiber diameter. Zeolite concentration and needle size did not affect the surface morphology significantly. The UV–vis spectra of the adsorption test showed that ∼93%, 85.5%, and 78% of methyl orange were adsorbed for 30, 50, and 100 mg L−1 initial dye concentration, respectively, within 11 min. The maximum adsorption capacity was found to be 95.33 mg g−1. Therefore, PMMA/zeolite nanofibrous membranes possess the adsorption capability toward effective dye rem

Electrospinning Nanoparticles-Based Materials Interfaces for Sensor Applications 2021-03-17

Electrospinning is a facile technique to fabricate nanofibrous materials with adjustable structure, property, and functions. Electrospun materials have exhibited wide applications in the fields of materials science, biomedicine, tissue engineering, energy storage, environmental science, sensing, and others. In this review, we present recent advance in the fabrication of nanoparticles (NPs)-based materials interfaces through electrospinning technique and their applications for high-performance sensors. To achieve this aim, first the strategies for fabricating various materials interfaces through electrospinning NPs, such as metallic, oxide, alloy/metal oxide, and carbon NPs, are demonstrated and discussed, and then the sensor applications of the fabricated NPs-based materials interfaces in electrochemical, electric, fluorescent, colorimetric, surface-enhanced Raman scattering, photoelectric, and chemoresistance-based sensing and detection are presented and discussed in detail. We believ

Transformation of TiO2 nanofibers by electrospinning 2021-03-17

In this work reports the crystalline phase transformation of electrospinning TiO2 nanofibres by annealing at high temperatures. The nanofibres chemical stoichiometry was determined by Energy-dispersive X-ray spectroscopy (EDS), which allowed find that the TiO2 crystal phase transformation is caused by oxygen vacancy generation. The TiO2 nanofibres diameter varied from 137.0 to 115.3 nm in the temperature range of 100–1000 °C, which was estimated by Scanning Electron Microscopy. The TiO2 nanofibres structural transformation from pure anatase to pure rutile structures, including the quasi-amorphous and anatase-rutile mixed phases has been confirmed by Raman scattering and X-ray diffraction. The Raman spectroscopy exhibits the anomalous behaviour for band broadening and shifting of Raman bands with increasing crystallite size that form the nanofibres. By X-ray diffraction was found that the nanofibres crystalline phases present as preferential growth direction (101) for anatase and (110)

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

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