Morphological Development of Immersion-Electrospun Polymer Products Based on Nonsolvent-Induced Phase Separation

In this study, the morphological development of polymer products in immersion electrospinning, based on a nonsolvent-induced phase separation (NIPS) mechanism, has been comprehensively delineated. The polymer concentration is considered the most significant factor in evaluating the morphology change of immersion-electrospun products. The structure formation process in immersion electrospinning is mainly due to the demixing of the solvent and nonsolvent, in contrast to conventional electrospinning in which solvent evaporation is critical. The former mechanism facilitates the formation of a series of polymer products with distinctive morphologies during immersion electrospinning. Specifically, as the polymer concentration increases, the product morphology changes from dispersed particles to highly aggregated particles, eventually forming bead-free strip/fiber forms. The present study is expected to provide insights into advanced polymer structures, which can be used in a broad range of applications.