Tuning Structure and Properties of Graded Triblock Terpolymer-Based Mesoporous Films

This talk will focus on the fabrication and performance of ultrafiltration membranes made from multiblock polymers, whose self-assembled structure promises superior selectivity for separating viruses and other undesirable solutes from solution.  Despite considerable efforts towards fabricating ordered, water-permeable, mesoporous films from block copolymers, fine control over pore dimensions, structural characteristics, and mechanical behavior remains a major challenge. To this end, we describe the fabrication and performance characteristics of graded mesoporous and hybrid films derived from the newly synthesized triblock terpolymer, poly(isoprene-b-styrene-b-4-vinylpyridine). The film structure comprises a thin selective layer containing vertically aligned and nearly monodisperse mesopores at a density of more than 10¹⁴ per m² above a macroporous support layer.  Solvent flow and solute separation experiments demonstrate that the terpolymer films have permeabilities comparable to commercial membranes, are stimuli-responsive, and contain pores with a nearly monodisperse diameter.  These results suggest that moving to multiblock polymers and their hybrids may open new paths to produce high performance graded membranes for a myriad of applications.