(609e) High Flux Porous Structure Formation in Isoporous Thin Film Membranes through Selective Domain Assembly

The peculiar morphologies of block copolymer (BCP) thin films offer an expansive platform to design and adjust different properties of the membranes by simply tuning the experimental parameters. This is especially applicable for the diblock copolymers where their domain assembly could easily be tailored before, during or after the thin film formation to study their affects on membrane characteristics with great control. In this work, we report a highly porous structure of an ultrafiltration membrane with poly(styrene)-b-poly(4-vinlypyridine) (PS-b-P4VP) BCP derived selective layer. The desired domain assembly in the asymmetric BCP films is promoted by adding different mass ratios of an active additive which selectively migrates into the domains. The films are then captured above polyethersulfone support layer and immersed in selective swelling solution to enable modified pore formation. Such membrane composites exhibited water flux rates above 300 Lm^-2h^-1bar^-1 which indicate an increase in interconnectivity of pores. Furthermore, the porosity of the ~120 nm selective layer is enhanced by adding homopolymer and solvent blends and later using quaternization process. The resulting pore morphologies in relation to their blend concentrations are measured using atomic force microscopy. The asymmetric membranes prepared with highly tunable pores are demonstrated to be effective for ultrafiltration applications.

- This work is supported with funding from NPRP grant 10-0127-170269 of QNRF, NSF grant DMR-1905996