NANOFIBER PRODUCTION [REVIEW]

Nanofibers are very thin fibers having diameters lower than 100 nm and their lengths might be as long as possible within production limits. The large surface area of nanofibers gives opportunity to functionalize them. Nanofibers have several applications including both applications for industrial production in many sectors and for research studies. Nanofibers find applications in energy devices such as solar cells, fuel cells and nanogenarators; in filtration applications (such as water/oil filtration, fine particle filtration, aerosol filtration, air filtration, nanoparticle filtration) and in several medical applications including antibacterial efficacy, wound healing, drug delivery and scaffolds for tissue engineering. There are several methods to produce nanofibers: Electrospinning, self assembly, phase separation, bacterial cellulose, templating, drawing, extraction, vapor-phase polymerization, kinetically controlled solution synthesis, conventional chemical polymerization for anyline. Electrospinning is the most widely used method to produce nanofibers.In electrospinning, a high electric field, which is in kilovolts, is applied to a polymer solution. The polymer solution is drawn from a syringe to a collector surface.Electrospinning requires usage of appropriate solvent, removal of evaporating solvent, an adequate power supply to overcome the viscosity and surface tension of the polymer solution; while, jet instability and jet control remain as challenges in electrospinning. Nanofiber production methods possess some disadvantages as: higher cost compared to conventional fiber production methods, health hazards such as inhale risk of nanofibers during production and keeping the environment safe from evaporating solvents used during nanofiber production. Up to date, many researches have been conducted on nanofibers and electrospinning; still, more controllable, more cost effective, more environmentally friendly and safer methods are of essential importance to future applications of nanofibers.