Electrospun Porous Nanofibers with Imprinted Patterns Induced by Phase Separation of Immiscible Polymer Blends

Nanofibrous nonwoven fabrics have attracted attention as porous adsorbents with high specific surface areas for the safe and efficient treatment of spilled organic dyes and petroleum. For this purpose, a method of fabricating porous nanofibers with high specific surface areas would be highly beneficial. In this study, the phase separation in nanofibers electrospun from blended solutions of immiscible polymers [poly(styrene) (PS) and poly(vinylpyrrolidone) (PVP)] was investigated. The removal of PVP as a sacrificial polymer afforded the imprinting of mesopores (40-70 nm) in the PS nanofibers. The effects of solution composition (PS/PVP in N,N-dimethylformamide) on the structure formation in the fibers were investigated. The nanofibers thus obtained could selectively adsorb low-molecular-weight hydrophobic dyes, such as Nile Red and Oil Red O. Thus, it is expected that the combined approach of electrospinning of immiscible polymer blends and phase separation-induced patterning can be applied to the fabrication of functional nanofibers for diverse applications.