Process optimization for gaining ultrafine nanofibers

The aim is generally to produce fibers with a well-determined fiber diameter which has a small standard deviation. Fibers should also be without defects [43], This can be obtained by adjusting the solution, process, and environmental parameters which affect electrospinning. 

Surfactants, such as glycerine can be used in these cases. Viscosity has jet-stabilizing effect, but on the other hand, higher repulsion forces are required to stretch a more viscous hquid. Below the proposed viscosity, bead formation on fibers can be seen, and further decrease of the viscosity leads to electrospraying. To avoid bead-forming instability, the viscosity and surface tension should be increased [25], or increasing the conductivity may help [82], 

Industrialization attempts for producing electrospun materials in a high volume 

Although electrospinning is a very simple, single-step and cost-effective process, it is important to emphasize that low productivity is the key problem or disadvantage of the method. It is also important to consider that nanofibers usually stand for less than 1 weight percent of hybrid PPCs, so it is still important to implement more efficient production technologies. 

Nanofibrous materials can be produced in industrial scales [85] and there are companies have produced nanofibers for over 40 years [86]. 

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