Low temperature regulated reverse interfacial polymerization for fabricating thin film composite membranes based on nanofibrous substrates

Abstract

In this study, a novel thin film nanofibrous composite (TFNC) nanofiltration (NF) membranes comprised of polyacrylonitrile (PAN) nanofibrous supporting layer and polyamide (PA) compact separating layer was constructed by low-temperature-controlled reverse interfacial polymerization (LTIP-R) at − 5 °C. The strategy for lowering the temperature of organic phase solution played a crucial role in forming a dense and thin PA layer on the PAN nanofibrous substrate with submicron pores. The results revealed that the reduced evaporation rate of organic phase at low temperature was contributed to maintaining a complete and uniform interface for the following reverse IP process, effectively overcoming shortcomings of surface incompleteness and easy infiltration of PA barrier layer. Owing to the reduced thickness and the enhanced wholeness of the PA separating layer via LTIP-R, the optimized TFNC membranes exhibited NF performance with great rejection of divalent salt ions (98.2%) and an improved permeation (13.3 L‧m−2‧h−1‧bar−1). This work would provide an efficient and facile method to fabricate high performance NF membranes for practical applications.