Interfacial Polymerization

Abstract

Abstract Thin‐film composite (TFC) membranes formed through interfacial polymerization have dramatically improved the performance of membrane‐based separation techniques. In particular, the reverse osmosis (RO) and nanofiltration (NF) processes have seen significant improvements in hydraulic productivity and solute rejections through this method, which allows for the placement of a very thin, dense selective layer onto a porous polymer support. Early composite membranes, which were formed using interfacial polymerization, were based on polymeric amines; however, it was ultimately shown that monomeric amines offered the best overall membrane performance. The interfacial polymerization reaction of two monomeric amines, m ‐phenylenediamine (MPD), and trimesoyl chloride (TMC), forms a polyamide and is the basis for most modern RO membranes. Membrane structure and performance can be well modulated through variation in monomer concentration, reaction time, posttreatment strategies, and miscibility enhancers. Despite their relative advantages, polyamide‐based membranes are susceptible to chlorine attack and therefore significant effort has focused on the development of chlorine‐tolerant versions. With the advent of nanomaterials, the use of nanoparticles and carbon nanotubes (CNTs) in mixed matrix membranes is an exciting new area of research. This article presents the fundamentals and history of interfacial polymerization in formation of RO membranes.