Morphology of electrospun fibers derived from High Internal Phase Emulsions

Abstract

High Internal Phase Emulsions (HIPEs) are known for their excessive volume of dispersed phase (volume fraction of dispersed phase Φd>0.74) and are primarily used for polymerization of continuous phase monomer(s) thereby generating porous systems in a single step. In the present work, electrospinning of HIPEs formed from aqueous solution of poly(vinyl alcohol) (PVA) dispersed in continuous phase comprised of poly(ε-caprolactone) (PCL) solution in toluene is conducted. Effect of variation in volume fraction of dispersed and continuous phase on fiber morphology was studied. Fibers of co-continuous morphology were obtained due to coalescence and dielectrophoresis of the higher electrically conducting dispersed aqueous phase than toluene containing continuous phase. Removal of PVA was later done by washing of fibers with water to evaluate the presence of two phases in the fibers and relate it to original HIPE morphology of the emulsions. Heterogeneous and surface nucleation of PCL and Brij-58 confined within electrospun fibers of HIPEs was studied in detail and related to the original HIPE structure.