The influence of salt and solvent concentrations on electrospun polyvinylpyrrolidone fiber diameters and bead formation

The electrospinning process is a useful technique to fabricate nanoscale filaments from polymeric solution. Its versatility and simplicity allows engineers and scientists to synthesize fibers for many applications. The diameters and morphologies of the electrospun fibers are dependent upon the electrospinning conditions and the composition of the electrospinning solution.In this work, the composition of the electrospinning solution for fabricating Polyvinylpyrrolidone (PVP) fibers was experimentally modified with the goal of fabricating smaller diameter fibers without the formation of bead structures in the fibers. The results show the average fiber diameter can be reduced significantly, from about 700 nm to about 100 nm, by adding deionized water to a solution of PVP in ethanol. However, the addition of deionized water into the PVP-ethanol solution increased the formation of beads in the fiber morphology. Further modification of the solution with ionic salts successfully reduced the formation of beads in the morphology of the electrospun fibers with average diameter less than 300 nm.