Shape-Selective Filtration Using Block Copolymer Membranes

There's a critical need for reliable and equitable access to safe drinking water, and it is a major and growing challenge worldwide. Safe and readily available water is important for public health, whether it is used for drinking, domestic use, food production, or recreational purposes. One method that has been of particular interest to purify water is using Ultra Filtration (UF) membranes with a pore size range of 1-100 nm. UF commercial membranes have found utility in the decontamination of drinking water, wastewater treatment, and membrane bioreactors. Unfortunately, UF membranes are limited by the stochastic pore sizes and undesirable surface chemistry which results in inadequate separations and prone to fouling. Alternatively, recent research shows that a more successful method to purify water is to utilize Block Copolymer (BCP) membranes. BCPs membranes have the capability to self-assemble into well-defined domains of uniform size thus improving size selectivity and fouling resistance. BCPs are casted as thin films where the self-assembled nanostructure serves as a template for pore generation. Pores are generated by selectively moving (etching) one of the domains and the pore size depends on the molar mass of the etchable domain. The most common morphology studied are cylindrical nanopores. As part of my SURF research program, we have developed slit based membrane using block copolymer lamellar structures and have demonstrated the shape selective filtration of Dextran using these membranes. Such membranes posses the potential for size selective filtration of proteins, viruses and pharmaceutical drugs.