Electrospinning Conditions Research Articles

Flexible electrospun fluorescent anisotropic conductive Janus-typed nanoribbon membrane

Flexible multiple-functional conductive anisotropic membrane made of one-dimensional directional nanomaterial has the potential applicative prospects in advanced electronic skin and strain sensor. Nevertheless, it is hard to prepare aligned polymeric composites with poly-functional high conductive anisotropy and excellent interface properties, so it has been a vital topic to fabricate and investigate such kind of composites. In this work, the fluorescent anisotropic-conduction Janus-typed nanoribbon array membrane (named as FAJNAM for short) with [Eu(TTA)3bipy/polymethylmethacrylate (PMMA)]//[carbon black (CB)/PMMA] Janus-typed nanoribbon as construction unit is prepared by di-axial parallel electrospinning with a di-axial parallel spinneret. Since CB will seriously affect the fluorescence intensity of the Eu(TTA)3bipy complex, through using Janus-typed nanoribbon as construction unit, Eu complex and CB can be confined in their own regions, realizing efficacious separation of fluorescent and electrical substances to significantly reduce the adverse effects between the two functions so as to obtain excellent red fluorescence and electrical conduction. The percolation zone of CB in Janus-typed nanoribbons membrane is determined. By adjusting the content of CB, the transition from insulation to conductivity of the FAJNAM can be realized. The highest anisotropic conduction ratio reaches ca. 108 when the CB content is 10 %. For the first time, the crucial of critical diffusion concentration of two-phase spinning solutions in the parallel electrospinning process is advanced and studied in depth. Furthermore, the relationship between the critical diffusion concentration and the conductive aeolotropism degree has been explored. The concept of critical diffusion concentration is also applicable to other di-axial parallel electrospinning to prepare multi-functional materials, which will be of great significance to optimize electrospinning conditions. This research provides new technical support for the preparation of highly flexible, conductive anisotropy composite materials.

Culture and maintenance of neural progressive cells on cellulose acetate/graphene‑gold nanocomposites

In this study, the first CA nanofibers were fabricated by electrospinning under optimal conditions: flow rate of 0.5 ml/h, a voltage of 20 kV, electrospinning distance of 15 cm, and an internal temperature of 25 °C, and humidity of 38%. The used Graphene/gold nanoparticles for CA performance improvement were examined by TGA, XRD, and SEM analysis. Then the CA/graphene‑gold nanocomposite was synthesized under optimum electrospinning conditions: flow rate 3 ml/h, voltage 20 kV, electrospinning distance 15 cm, internal temperature 26 °C, and humidity 36%. The SEM images revealed that the nanofibers' thicknesses of Graphene‑gold NPs (CA1) and Chitosan (CA2) were 350 and 120 nm, respectively. The XRD diagrams of CA0, CA1 and CA2 revealed the peaks at 2θ, 8°, and 21° with Miller indices of (001) and (110) are related to CA (CA0), which proves its presence in other scaffolds. The FTIR analysis of samples indicated the presence of graphene‑gold NPs in scaffolding CA1 and CA2. The CA2 nanofibers exhibited a high-water absorption capacity of about 2500% with the water contact-angle and Swelling method. The antibacterial properties of this nanocomposite were also confirmed by an antibacterial test on Staphylococcus aureus bacteria. The growth of Schwann cells on three scaffolds showed the highest growth of cells on CA1 scaffolds.

Variable Direct Electromechanical Properties of As-Electrospun Polystyrene Microfiber Mats with Different Electrospinning Conditions.

As-electrospun microfiber mats comprising atactic polystyrene (aPS), a low-cost commodity polymer, have demonstrated beneficial electromechanical properties. However, the variability of the electromechanical properties of fiber mats produced using different electrospinning conditions has not been investigated. Therefore, herein, the direct electromechanical properties of aPS fiber mats produced using different deposition times (tdep) and electrospinning voltages (VES) are investigated. The resulting apparent piezoelectric d constant (dapp) of the fiber mats demonstrates a specific peak value for tdep as high as ~1600 pC N−1 under 1-kPa pressure application after ~0.2-kPa pre-pressure application, although the dapp of the fiber mats produced with some conditions is nearly zero pC·N−1. Furthermore, the peak position of dapp with tdep is fundamentally determined with σEff0/YD(h-hpre) [σEff0: effective surface charge density, YD(h-hpre): secant modulus of elasticity]. Charge distribution models for fiber mats with different tdep are established. The models explain the characteristics of the significant changes in YD(h-hpre) and σEff0 with tdep. These findings provide significant directions for the production of fiber mats with improved direct electromechanical properties.

Enhanced thermal conductivity of poly(aryl ether nitrile ketone)/functionalized boron nitride composites by electrospinning–hot press technique

AbstractIn this study, poly(aryl ether nitrile ketone)/functionalized boron nitride (PEK‐CN/f‐BN) composites fibers were prepared by solution blending followed by electrospinning technique. And the thermally conductive PEK‐CN/f‐BN nanocomposites were fabricated via hot press method. Octadecyltrimethylammonium Bromide (OTAB) was performed to functionalize the surface of boron nitride (BN) fillers, which were utilized as thermally conductive fillers to fabricate the corresponding PEK‐CN/BN composites. The thermal conductivity coefficient (λ) of the PEK‐CN/f‐BN composites (25 wt% f‐BN) was 0.702 W/mK, and the PEK‐CN/BN composites (25 wt% unfunctionalized BN) was 0.649 W/mK, whose λ is more than 200% higher than the λ of pure PEK‐CN (0.251 W/mK). Meantime, compared to the pure PEK‐CN, the glass‐transition temperature (Tg) of the PEK‐CN/f‐BN composites was increased from 228.10 to 232.98°C, and the thermal stability of the PEK‐CN/f‐BN composites has been improved as well. It was also noticed that, under the ideal electrospinning conditions, when the content of BN and f‐BN attached to 25 wt%, the storage modulus (E′), loss modulus (E″), and dielectric loss tangent (tan δ) values of the PEK‐CN/BN composites and PEK‐CN/f‐BN composites were higher than that of pure PEK‐CN.

Magnetoactive electrospun hybrid scaffolds based on poly(vinylidene fluoride‐co‐trifluoroethylene) and magnetite particles with varied sizes

AbstractThe development of functional magnetoactive materials fabricated in the form of electrospun scaffolds is of paramount importance for modern medicine and pharmaceuticals. To precisely control the morphology and magnetic properties of the composite magnetoactive scaffolds, the electrospinning conditions, incorporation method of magnetic particles into the polymer solution to avoid agglomeration, and the shape/size of the particles should be thoroughly studied. In this study, hybrid magnetoactive scaffolds based on poly(vinylidene fluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)), doped with either unmodified magnetite (Fe3O4) or magnetite particles modified with oleic acid (Fe3O4/OA), have been fabricated by electrospinning. Modification of magnetite particles by oleic acid results in the formation of nanosized particles in comparison with submicron‐sized Fe3O4 particles (37 vs. 329 nm), which reveal a greater affinity to P(VDF‐TrFE) due to their hydrophobic surface. Composite scaffolds prepared using 30 wt% polymer solution with 8 wt% Fe3O4 and Fe3O4/OA reveal saturation magnetization values of 9.14 and 5.8 emu/g, respectively. The saturation magnetization of composite scaffolds agrees well with the saturation magnetization of the initial magnetites. Considering the better dispersion of Fe3O4/OA in the polymer solution, a series of composite scaffolds with 4 and 12 wt% concentrations of magnetite have been studied. Cytotoxicity tests demonstrated that all the fabricated composite scaffolds are nontoxic to human cells. Variation of magnetite particles content in the polymer fibers enables to obtain composite scaffolds with tailored saturation magnetization, which can be potentially used as perspective magnetoactive and magnetoelectric materials for biomedical application.

Designing a novel 3D nanofibrous scaffold based on nanoalloy AuAg NPs (AuAg@ PAN NFs) for osteogenic differentiation of human adipose derived mesenchymal stem cells (hADMSCs)

The present study applied a new strategy to modify the surface properties of a polymeric matrix with the aim of forming an osteogenic scaffold with a stable structure and better osteo-inductive potential. To this purpose, we applied appropriate electrospinning conditions to design the nanofibrous scaffold of AuAg@ polyacrylonitrile (P) nanofibers (AAP NFs), based on incorporation of the AuAg nanoparticles (AA NPs) which were prepared by ultrasound irradiation, with an electrospinning solution of polyacrylonitrile. This study has combined structural properties (crystalline, morphology, roughness) and surficial properties (mechanical and wettability) of fibrous samples, in order to elucidate the role of surface modification and formation of a stable fibrous scaffold in osteogenic differentiation. The XRD and FT-IR findings showed that the all crystalline properties of hexagonal system and the intensity of related IR-bands were changed. This modification caused the removal a smooth outer fiber layer of the P NFs and the creation of chunky shapes of AA NPs on the surface of the corresponding fibrous sample, which were confirmed by enhancing Ra values. The nanofibrous scaffold with 2% AA NPs disclosed the best mechanical performance and wettability. Finally, we showed that AAP NFs, not only improved cell adhesion, but also induced osteogenic differentiation of human adipose derived mesenchymal stem cells(hADMSCs) more efficiently than P NFs and tissue culture plates (TCPs).

Fabrication and investigation potential effect of lentinan and docetaxel nanofibers for synergistic treatment of breast cancer in vitro

AbstractBreast cancer has a high prevalence among women which has high recurrences even after common therapies, so using nanofibers that contain natural compounds along with antineoplastic drugs locoregionally can be a novel supportive strategy. In this study, hot water extracted lentinan from Lentinula edodes (TMU340) was purified by ion‐exchange chromatography. The effects of electrospun PVA/lentinan/docetaxel nanofibers were determined on HER3 expression in MCF‐7 cell line. Lentinan concentration was determined at 0.243 mg/ml. The optimal electrospinning conditions were 15 kV, 15 cm, and 1 ml/h. The HER3 expression of cells treated with PVA/lentinan/docetaxel nanofibers obtained 0.52 in the most effective concentration at 72 h. Based on the results, PVA/lentinan/docetaxel nanofibers have shown appropriate synergistic effects on breast cancer. Therefore, the utilization of lentinan as a natural compound with a common chemical anticancer drug and nano‐drug delivery system can be considered as a promising suggestion within the treatment of cancer.

Spontaneous Formation of 3D Breast Cancer Tissues on Electrospun Chitosan/Poly(ethylene oxide) Nanofibrous Scaffolds.

Three-dimensional (3D) tissue culture has attracted a great deal of attention as a result of the need to replace the conventional two-dimensional cell cultures with more meaningful methods, especially for understanding the sophisticated nature of native tumor microenvironments. However, most techniques for 3D tissue culture are laborious, expensive, and limited to spheroid formation. In this study, a low-cost and highly effective nanofibrous scaffold is presented for spontaneous formation of reproducible 3D breast cancer microtissues. Experimentally, aligned and non-aligned chitosan/poly(ethylene oxide) nanofibrous scaffolds were prepared at one of two chitosan concentrations (2 and 4 wt %) and various electrospinning parameters. The resulting fabricated scaffolds (C2P1 and C4P1) were structurally and morphologically characterized, as well as analyzed in silico. The obtained data suggest that the fiber diameter, surface roughness, and scaffold wettability are tunable and can be influenced based on the chitosan concentration, electrospinning conditions, and alignment mode. To test the usefulness of the fabricated scaffolds for 3D cell culture, a breast cancer cell line (MCF-7) was cultured on their surfaces and evaluated morphologically and biochemically. The obtained data showed a higher proliferation rate for cells grown on scaffolds compared to cells grown on two-dimensional adherent plates (tissue culture plate). The MTT assay revealed that the rate of cell proliferation on nanofibrous scaffolds is statistically significantly higher compared to tissue culture plate (P ≤ 0.001) after 14 days of culture. The formation of spheroids within the first few days of culture shows that the scaffolds effectively support 3D tissue culture from the outset of the experiment. Furthermore, 3D breast cancer tissues were spontaneously formed within 10 days of culture on aligned and non-aligned nanofibrous scaffolds, which suggests that the scaffolds imitate the in vivo extracellular matrix in the tumor microenvironment. Detailed mechanisms for the spontaneous formation of the 3D microtissues have been proposed. Our results suggest that scaffold surface topography significantly influences tissue formation and behavior of the cells.

Preparation of Polyketone Micro/nanofiber Membrane based on Electrospinning Condition and Its Application in Oil-Water Separation

Preparation of Polyketone Micro/nanofiber Membrane based on Electrospinning Condition and Its Application in Oil-Water Separation

Development and evaluation of novel nanofibers based on mango kernel starch obtained by electrospinning

This work reports on the development of fibers based on natural mango kernel starch (MKS) with diameters in the nanoscalse by means of the electrospinning technique. MKS was extracted from mango kernels and two synthetic polymers, namely polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), were blended with MKS in order to improve its spinnability, obtaining MKS/PVA and MKS/PVP fibers with a 10 wt% of total polymer concentration. Several electrospinning conditions (voltage and flux) were tested in solutions of MKS concentrations ranging from 0 to 5 wt% for both group of fibers. The morphology of all the fibers was evaluated by field emission scanning electron microscopy (FESEM) and their topography was analysed by means of atomic force microscopy (AFM). MKS/PVA nanofibers were obtained with a diameter range from 0.146 to 0.315 μm, with a “smooth fiber concentration threshold” of 3 wt%, while MKS/PVP, fibers with diameters from 0.080 to 0.339 μm were produced, but 5 wt% MKS concentration fibers were beaded fibers, as a result of an excess in starch concentration. Finally, the roughness of the optimal fibers showed quite a similar trend to that of fiber diameter, presenting roughnessess between 80 and 343 nm.

Self-Assembled NBR/Nomex Nanofibers as Lightweight Rubbery Nonwovens for Hindering Delamination in Epoxy CFRPs.

Still today, concerns regarding delamination limit the widespread use of high-performance composite laminates, such as carbon fiber-reinforced polymers (CFRPs), to replace metals. Nanofibrous mat interleaving is a well-established approach to reduce delamination. However, nanomodifications may strongly affect other laminate thermomechanical properties, especially if achieved by integrating soft materials. Here, this limitation is entirely avoided by using rubbery nitrile butadiene rubber (NBR)/Nomex mixed nanofibers: neither laminate stiffness nor glass-transition temperature (Tg) lowering occurs upon CFRP nanomodification. Stable noncrosslinked nanofibers with up to 60% wt of NBR were produced via single-needle electrospinning, which were then morphologically, thermally, spectroscopically, and mechanically characterized. NBR and Nomex disposition in the nanofiber was investigated via selective removal of the sole rubber fraction, revealing the formation of particular self-assembled structures resembling quasi-core–shell nanofibers or fibril-like hierarchical structures, depending on the applied electrospinning conditions (1.10 and 0.20 mL/h, respectively). Mode I and Mode II loading tests show a significant improvement of the interlaminar fracture toughness of rubbery nanofiber-modified CFRPs, especially GI (up to +180%), while GII enhancement is less pronounced but still significant (+40% in the best case). The two nanofibrous morphologies (quasi-core–shell and fibril-like ones) improve the delamination resistance differently, also suggesting that the way the rubber is located in the nanofibers plays a role in the toughening action. The quasi-core–shell nanofiber morphology provides the best reinforcing action, besides the highest productivity. By contrast, pure Nomex nanofibers dramatically worsen the interlaminar fracture toughness (up to −70% in GI), acting as a release film. The achieved delamination resistance improvements, combined with the retention of both the original laminate stiffness and Tg, pave the way to the extensive and reliable application of NBR/Nomex rubbery nanofibrous mats in composite laminates.

Self-organization of unimolecular micelles in beam stream for functional mesoporous metal oxide nanofibers

The use of linear amphiphilic block copolymers as templates is an important method for the preparation of mesoporous materials. However, the obtained assemblies are usually sensitive to synthetic conditions, which impedes the preparation of such mesoporous materials in certain environments. Herein, we report a universal strategy applying an amphiphilic multi-arm triblock copolymer in the preparation of mesoporous metal oxide nanofibers (NFs) using one metal oxide (TiO2, ZrO2, WO3, CeO2), or two (TiO2/WO3, TiO2/ZrO2, TiO2/CeO2) and three (TiO2/WO3/CuO) metal oxides as composites. The template consists of modified β-cyclodextrin as the center of the macromolecule which is attached sequentially to a block of polystyrene, poly(acrylic acid), and poly(ethylene oxide). Under electrospinning conditions, stable unimolecular micelles are formed and effectively co-assemble with metal ions to form fibrous nanostructures. As indicated by various characterization methods, the synthesized TiO2 and its derived composite NFs maintain a straight and continuous fibrous structure after calcination, and TiO2 NFs exhibit uniform mesopores of 10.8 nm in diameter and a large Brunauer-Emmett-Teller surface area of 143.3 m2 g−1. Benefiting from the characteristic structure, still present after modification, Pt-decorated mesoporous TiO2 NFs display excellent ability in the visible-light photocatalytic degradation of tetracycline, which is superior to the commercial P25 catalyst. This study reveals a promising strategy for the preparation of fibrous mesoporous metal oxides.

Semitransparent Perovskite Solar Cells with Enhanced Light Utilization Efficiencies by Transferable Ag Nanogrid Electrodes

Solar cells that are semitransparent and highly efficient can find diverse applications in automobile windows, building walls, and wearable devices. Here, we present a semitransparent perovskite thin-film solar cell with an Ag nanogrid transparent electrode, where electrospun poly(ethylene oxide) (PEO) nanofibers are used as an etching mask. Directional electrospinning has allowed us to obtain a grid-shaped electrode of well-aligned Ag nanogrids. The performance of transparent electrodes can be controlled by the electrospinning conditions and the choice of substrate materials. We theoretically analyze the transmittance and sheet resistance of the electrode. Furthermore, transferable Ag nanogrid transparent electrodes are fabricated on poly(dimethylsiloxane) (PDMS) substrates for application in semitransparent perovskite solar cells. Using an electrode that shows a high transmittance (92.7%) with a low sheet resistance (18.0 Ω·sq-1), a semitransparent perovskite thin-film solar cell demonstrates average visible wavelength transmittance, power conversion efficiency, and light utilization efficiency rates as high as 25.2, 12.7, and 3.21%, respectively.

Preparation, Characterization and Antibacterial Activity of Malva Sylvestris L. Seed Extract Containing Novel Electrospun PVA Nanofibers

Medicinal plants have been a great source for pharmaceutical agents. However, prossessing these raw sources to turn into therapeutic drugs requires highly complex technologies and expensive methods. Malva sylvestris L. is a commonly used vegetable in traditional and ethnoveterinary medicine because of its antimicrobial and anti-inflammatory properties. Therefore, in this study we used PVA/M. sylvestris L. seed (MSs) extract biocomposites to produce nanofibers with electrospun technique. M. sylvestris L. seed extracts were prepared and divided into fractions with 20% ACN. The metabolites in MSs extract characterized by Q-TOF LC-MS. Biocomposites with different ratios of both polymer and extract were prepared for nanofiber production. Bionanofibers have been produced from these biocomposites with optimized electrospinning conditions and their morphological analysis has been performed using SEM and FTIR techniques. Nanofibers had average diameters within the range of ∼180–244 nm. They were also found to have antibacterial activity against several microorganisms including Gram-negative (P.aeruginosa and E.coli) and Gram-positive (S.aureus and E.faecalis) bacteria. These newly generated bionanofibers with antibacterial properties hold great potential to be used in medical applications and food packaging.

Enrichment behavior of electrospun PVDF nanofiber membranes for simultaneous spectrophotometric determination of mixed organic acids in water

Electrospun nanofiber membranes (ENMs) of polyvinylidene fluoride which is known as solid phase extraction materials were fabricated through electrospinning technology. Different electrospinning conditions including polymer content, spinning voltage and flow rate were investigated. The optimal operation conditions for electrospun process were set at 12% of PVDF mass fraction, 12 kV of spinning voltage, 0.5 mL h−1 of flow rate, 15 cm of receiving distance, 22 °C of spinning temperature and 45% of environmental humidity. The self-made ENMs were introduced into a combined method of radial electric focusing solid phase extraction enrichment, ultrasonic elution, UV-Vis detection and PLS calculation for determining benzoic acid, phthalic acid and p-toluene sulfonic acid in aqueous samples simultaneously. The calculation results of unknown sample show that the concentrations of benzoic acid, phthalic acid and p-toluene sulfonic acid were 4.416 mg L−1, 4.976 mg L−1 and 5.27 mg L−1, respectively. The relative standard deviation values of each component are all less than 2% with a relative recovery of 84–119%. The ENMs illustrate their fascinating application prospects in determining trace complex materials in aqueous samples.

Electrospun Poly(methyl methacrylate)/TiO2 Composites for Photocatalytic Water Treatment.

Electrospinning was successfully used for the one-step fabrication of poly(methyl methacrylate) (PMMA) fibers loaded with an inorganic photocatalyst—titanium oxide (TiO2). By tuning the PMMA/TiO2 ratio and the electrospinning conditions (applied voltage, needle tip-to-collector distance, and flow rates), PMMA/TiO2 composites with selected organic/inorganic ratios, tailored designs, and targeted properties were obtained. The morphology of the electrospun composites was affected by the amount of TiO2 incorporated into the PMMA fibers. In addition, the inorganic photocatalyst had an impact on the wettability, thermal stability, and optical properties of the electrospun composites. In particular, the surface wettability of the composites was strongly influenced by UV light irradiation and from hydrophobic became superhydrophilic. Moreover, PMMA/TiO2 composites had enhanced tensile strength in comparison with those of bare PMMA mats. The electrospun PMMA/TiO2 composites showed excellent photocatalytic efficiency against the model organic pollutant—methylene blue—which is very promising for the future development of membranes that are highly efficacious for photocatalytic water treatment.

Electrospun nanofibrous polyether-block-amide membrane containing silica nanoparticles for water desalination by vacuum membrane distillation

In this work, hydrophobic nanofibrous membranes based on polyether-block-amide (PEBAX-2533) were prepared by the electrospinning technique for using in the vacuum membrane distillation (VMD) process for water desalination applications. In the first part of this study, the influence of the electrospinning conditions like polymer concentration, surfactant concentration, applied voltage, spinneret to collector distance, feed injection rate and spinneret diameter on the morphology of the electrospun mats was investigated and optimized to obtain uniform, bead-less and defect-free nanofibrous PEBA membranes. In the second part, the electrospun nanofibrous SiO2/PEBAX-2533 membranes were fabricated by incorporating silica nanoparticles into the polymer solution. The morphology, structure, and surface properties of the prepared nanofibrous SiO2/PEBA membranes were characterized by the SEM, FTIR, OCA, and tensile strength tests. Likewise, the VMD performance of the prepared electrospun SiO2/PEBA membranes was studied for the desalination of NaCl aqueous solutions at various operating conditions. It was observed that the VMD performance of the prepared electrospun nanofibrous SiO2/PEBAX-2533 membrane containing 8 wt% of silica nanoparticles had the best separation performance in terms of the water flux, flux decline and TDS content of the permeate stream. Finally, a comparison between the prepared nanofibrous SiO2/PEBAX-2533 membrane and a commercial PVDF membrane revealed that the VMD separation performance and long-term stability of the electrospun membrane were much better than those of the commercial PVDF membrane.

Electrospinning of epoxy fibers

Drawn epoxy fibers possess increasingly high mechanical properties when their diameter is decreased down to a limit of about 10 μm. Smaller diameters with even higher properties can potentially be obtained by electrospinning. Yet, electrospinning of standalone epoxy fibers has not been possible so far, because of the reactivity of epoxy and the fragility of such fibers. These difficulties are overcome in the present study by dissolving the epoxy in methyl ethyl ketone solvent, and achieving suitable electrospinning conditions by controlling the degree of epoxy crosslinking in the solution. The fibers are captured on a net screen, with the positive electrode placed behind it. The resulting electrospun fibers exhibit about 80% higher strength and stiffness compared to bulk epoxy, and striking 900% higher elongation and 1200% higher toughness. Also observed is a size-dependence of the strength on the fiber diameter, which shows a sharp strength rise to more than 300 MPa (compared to about 70 MPa in bulk epoxy) in fibers of diameters down to 3 μm. This rise in properties is likely due to anisotropic molecular rearrangement resulting from the strong stretching forces induced by electrospinning. Highly performant epoxy nanofibers could find applications in diverse fields, including reinforcement in composites, sensors, coatings and electronic devices.

Electrospun natural rubber latex biocomposite for scaffolds in tissue engineering

Fibrous scaffold along with seed cells are essential players for engineered tissue regeneration. Recently, PLGA/epoxidized poly(isoprene) dense membranes have been evaluated for cell growth and have shown satisfactory results. However, porous and fibrous structures suitable for obtaining 3D supports have not yet been evaluated for the PLGA/epoxidized poly(isoprene). The present work aimed to establish the electrospinning conditions for obtaining electrospun membranes with a smaller diameter of fibers and adequate morphology, which were characterized in vitro by their physical, chemical and biological properties. The best electrospun fibers were obtained from the following conditions: an applied voltage of 15 kV, a needle-collector distance of 20 cm and, a flow rate of 5 mL/h. The functional groups of the polymers involved in the blend did not show any changes. The mechanical properties of the electrospun membranes are within the lower limits known to human skin and some soft tissues. The in vitro degradation test showed a loss of mass of approximately 20% in 28 days. Significant adhesion and proliferation of human adipose–derived mesenchymal stem cells were demonstrated, indicating that there was cellular penetration into the scaffold and proliferation. Therefore, the preliminary results suggest that the electrospun PLGA/epoxidized poly(isoprene) membranes have high potential for application as a 3D tissue engineering scaffold.

Electrospinning of polyvinylidene fluoride membranes: effect of membrane composition and fabrication conditions

Membrane fabrication by the electrospinning can provide tunable structure membranes with interconnected pores, large surface area, and high porosity. This study focuses on studying the effect of different membrane compositions (i.e., polymer concentration and inorganic additives) and electrospinning conditions (i.e., internal needle diameter, tip to collector distance, and feed flow rate) on the quality of polyvinylidene fluoride (PVDF) flat sheet membrane. A homogeneous dope solution was prepared by dissolving the PVDF in a mixture of dimethylacetamide (DMAc) and acetone. By using a scanning electron microscope (SEM), the electrospinning conditions producing beadles fibers are as follows: 16 wt% polymer concentration, 0.004 wt% LiCl concentration, 0.51 mm internal needle diameter, 15 cm tip to collector distance, feed flow rate of 1 ml/hr. Further analysis was conducted by using Fourier Transform Infrared Spectrometer (FTIR) and X-Ray Diffraction (XRD) to assess the impact of electrospinning on fibers elemental composition. Additionally, static water contact angle, porosity, fiber diameter, and pore size measurements reveal the formation of submicron hydrophobic fibers with random alignment.