Comparative Study of Polymer Dissolution Techniques for Electrospinning

A systematic investigation was performed to compare the electrospinnability of aqueous polyethylene oxide (PEO) solutions prepared using ultrasonication and mechanical stirring. A series of experiments with fixed electrospinning parameters was used to investigate the changes in solution viscosity, nanofiber deposition area and nanofiber morphology with respect to their solution processing method and polymer concentration. This work puts emphasis on the variations related to the solution properties rather than the electrospinning parameters. The viscosity of each solution showed that the viscosity of ultrasonically processed solutions was significantly lower compared to mechanically stirred solutions with the same polymer concentration. The difference is primarily related to the chain scission induced by sonication of the polymer- leading to a significant effect on their electrospinnability. The transition from beads to nanofibers for each solution was identified by studying the morphology using scanning electron microscopy (SEM). For mechanically stirred PEO solutions, nanofibers were successfully electrospun beginning with a polymer concentration of 6 wt% up to 8 wt%. The concentration ranges for producing nanofibers was between 8 wt% and 12 wt% for solutions prepared by ultrasonication. The study was further extended to investigate the electrospinnability of PEO solutions mixed with 2 wt% silicon carbide (SiC) nanoparticles. Nanocomposite nanofibers electrospun from PEO-SiC solutions exhibited an increase in continuous nanofibers with increasing concentration of the solutions. The results show that ultrasonic processing can be used to prepare the polymer solutions for electrospinning, which can reduce the processing time significantly and process a solution at higher concentration, compared with the conventional mechanical mixing.