Shape-selective filtration using lamellar block copolymer based slit membranes

The growing need for highly efficient water purification and bioseparations necessitates innovations in ultra-filtration membranes. Block copolymer (BCP) membranes have emerged as a promising player for efficient ultra-filtration due to their uniform pore sizes and sharp cut-offs. Most of the work in BCP membranes has focused on using cylindrical pores. In this work, we have developed novel slit-based membranes using lamellar block copolymers. The lamellar BCPs are vertically oriented in one step film casting process by tuning the solvent evaporation rates with additives. The vertically oriented BCPs are converted to slit membranes using a wet etching process. The pore sizes of these slit-based membranes are measured using surface characterization and filtration cut-off experiments. We demonstrate the enhanced separation of 1-D nanomaterials as compared to the 0-D nanomaterials using these slit-based membranes, which is facilitated by the shape similarity of 1-D nanomaterials with the nano-slits. Such membranes possess the potential for shape-selective filtration of biomaterials such as proteins, viruses, and pharmaceutical drugs and open avenues for shape-selective filtration across a spectrum of applications.