Towards Analysis and Optimization of Electrospun PVP (Polyvinylpyrrolidone) Nanofibers

Table 1

Effect of electrospinning factors on fiber morphology.

Control parameters	Effects on fiber morphology
High voltage	(i) The fiber diameter value reduces with the increase in voltage supplied due to the higher stretching of polymer solution [17].; (ii) Higher voltage will increase the evaporation rate that dries the solvent faster [28, 29].; (iii) Lower voltage values result in reduced flight time of the polymer jet, which increases the possibility of obtaining smoother fibers [30].
Concentration	(i) The fiber diameter value increases with a higher concentration of polymer solution.; (ii) With lower concentrations, defects in the form of beads start to appear on the nanofiber mat.; (iii) Possibility of electrospraying also increases on lower concentrations [8, 12].
Rotational speed	(i) The average fiber diameter value is higher with a stationary rotor than a rotating collector.; (ii) The diameter of fibers decreases with an increase in rotating collector RPM, but the decrease in value is not significant compared to other parameters [31].
Collecting distance	(i) Increasing the distance will increase the time of flight, resulting in stretched and further elongated fibers [30].; (ii) Beads start to appear with a higher distance between the needle & the collector.; (iii) Formation of beads also takes place with lower distances as the polymer jet does not experience a sufficient time to solidify [32, 33].; (iv) The optimum distance is required to obtain smooth fibers [17].
Flow rate	(i) The fiber diameter decreases with the lower flow rate of polymer solution because it provides more time for stretching [17].; (ii) Higher flow rate values yielded thicker fibers with beads as the drying time for the fibers reduces [33].