The effect of viscosity and filler on electrospun fiber morphology

Electrospinning is a simple technique to create nanometer-scale polymer fibers by application of a large static voltage to a viscous polymer solution, or spin-dope. At polymer concentrations higher than the critical concentration, above which polymer entanglement can occur, it was found polymer fibers could be electrospun, provided the spin-dope solution was sufficiently viscous. The requisite viscosity could be obtained by increased polymer concentration or by inclusion of insoluble filler, titanium dioxide in this case. Electrospun fibers of polyethylene oxide (PEO) were successfully fabricated that consisted of as little as 25 wt.% polymer. The remainder of the fiber weight consisted of titanium dioxide (TiO2) particles that could not be electrospun alone. We demonstrate that it is possible to create a high-surface area structure of a material that cannot be electrospun by the inclusion of a small amount of polymer.