In the textile industry, although there are several methods for obtaining sub-micro-or nanofibres, electrospinning perhaps is the most versatile process. Electrospinning has been recognized as a feasible technique for the fabrication of continuous polymeric nanofibre yarns desired in the textile industry. Various materials including polymers, composites, ceramics and metals have been successfully electrospun into nanofibres in recent years mostly in solution and some in the melt. Potential applications based on electrospun nanofibres as a new-generation material in the textile industry will be realized if suitable nanofibre yarns become available to textile processes like weaving, knitting and embroidery. In this review, we present, from a textile viewpoint, a comprehensive overview of processing technologies of polymeric nanofibres in the textile industry; however, the emphasis here is focused on electrospinning. In particular, we choose to concentrate on a detailed account of research activities on the yarns and fabrics composed of electrospun nanofibres. Our discussion is concluded with some personal perspectives on the future challenges for the development and optimization of yarns based on electrospun nanofibres.

Electrospinning is a well‐established and intensively investigated methodology, and is currently the only known technique that can fabricate continuous nanofibres. The major challenge associated with electrospinning is its production rate, compared with that of conventional fibre spinning. However, the understanding of the scale‐up possibility of the electrospinning process is still in its infancy. Substantial up‐scaling of electrospinning may pave the way for applications of nanofibre assemblies (i.e. yarns) not accessible otherwise in conventional textile processes, such as weaving, knitting and braiding. Here we summarize recent advances regarding the enhancement of electrospinning throughput with special emphasis on multiple jets from multi‐needles and the free surface of polymer solutions. Copyright © 2009 Society of Chemical Industry

No abstract

A metallic needle is most often used in conventional electrospinning, where a point-plate electric field with nonuniform distribution is formed in singleneedle electrospinning (SNE). Low flow rate in SNE has restricted the application of electrospinning on an industrial scale. Multiple needles have been introduced to enhance the flow rate. However, multiple needles make the electric field distribution much more complex. To resolve this problem, alternative electrospinning setups with more uniform electric field have to be developed. Flat spinnerets have been demonstrated to replace the needle in SNE setups. The operating diagrams for flat spinneret electrospinning (FSE) were determined and differed significantly from those for SNE. Nanofibers produced by FSE were more uniform than those from SNE. These differences were explained by the differences in electric fields simulated using finite element analysis (FEA).

Electrospun nanofibers are most often produced by needle electrospinning process, which has inherent disadvantages like clogging and low efficiency. In this study, an alternative needleless electrospinning process is reported for the fabrication of nanofibers based on a novel spinneret. Firstly, a spinneret with a 0.5‐mm diameter hole in the middle of a flat plastic cap was custom‐made that may be readily scaled up for mass production. Then, polyethylene oxide (PEO) aqueous solution with 6.0 wt% concentration was used to demonstrate the needleless electrospinning process. The processing window for the jet formation in the flat spinneret electrospinning process was determined. The relationships between various processing parameters (applied voltage, working distance, and flow rate) and the resultant PEO nanofibers were also investigated. It was found that stable fluid jet launched from the tip of the coned droplet anchored at the rim of the hole and formed fibers. The morphology and diameter of electrospun fibers were examined using scanning electron microscopy. The results show that PEO nanofibers produced by this needleless electrospinning have similar structure and morphology to those from the single needle source. Finally, the hole number of spinneret was increased to four holes, which was still able to produce smooth nanofibers with a higher production rate. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers