**2.3. Conductivity**

High conductivity of processed material means a greater number of net charges on the jet when high voltage is loaded, therefore, a smaller fiber diameter can be attained by elevating the conductivity. Higher conductivity also may cause a drastic whipping of the electrospun jet, especially for polymer solutions, however, this may lead to a wide diameter distribution of the electrospun, non-woven fabrics. A widely used method to improve conductivity is by adding salts [28-29], pyridine [30], or carbon nano tube(CNT) [31] in polymer solution or polymer melts. However, this may change the original fiber properties. Some researchers have investigated additives that evaporate when jetting [32].
