High filtration performance thin film nanofibrous composite membrane prepared by electrospraying technique and hot-pressing treatment

Abstract

For conventional powder coating technology, powder coating materials were directly coated onto the target surface and then heated and cured to form a coat. Inspired by this technology, a facile route for fabrication of thin film nanofibrous composite (TFNC) membrane consisting of a nanofibrous substrate and a hydrophilic barrier layer was developed by electrospraying poly(vinyl alcohol) (PVA) nanobeads onto the electrospun polyacrylonitrile (PAN) substrate and following by hot-pressing treatment assisted by moistening absorption. Water molecules from absorbed moisture acted as “plasticizer” and could facilitate PVA melting. The moistened electrosprayed PVA nanobeads could be easily melted or softened to be pressed imperceptibly into an integrated barrier film on the supporting layer at a certain temperature. The depositing time of PVA electrospraying, moistcuring time, thermal treatment temperature and time were optimized to achieve an integrated, nonporous PVA barrier layer. The resulting barrier layer was chemically crosslinked and its filtration performance can be finely controlled by different PVA crosslinking degree. Especially, the optimized PVA/PAN TFNC membrane possessed high ultrafiltration performance in BSA filtration tests with water flux 173.0L/m2h and rejection above 98.0% at low feeding pressure 0.3MPa. This work may provide a practical feasibility for water filtration application.