Star polymer-assembled thin film composite membranes with high separation performance and low fouling

Thin film composite (TFC) membranes have attracted intense interest due to applications in various molecular separation processes including water purification, gas separation, organic solvent separation and saline-gradient energy production. In particular, growing global demands for clean water and reduced energy consumption have raised interest in highly permselective and low fouling TFC membranes for water treatment and desalination. This drive has led to the design of new molecular structures of TFC membranes using advanced materials. Here, we designed a new building block material, a star-shaped polymer, which can be assembled into the selective layer of the TFC membrane via a commercial interfacial polymerization (IP) technique. This ideal 3-dimensional compact globular geometry along with high density end-functional groups enabled the realization of membranes with higher permselectivity as well as superior antifouling properties even compared to commercial membranes. We demonstrate the remarkable versatility of this building block by using the same starting materials to fabricate membranes that can function either as nanofiltration or reverse osmosis membrane depending on the IP process conditions, which is not feasible with the conventional materials used in membrane fabrication.