Virus filtration membranes prepared from nanoporous block copolymers with good dimensional stability under high pressures and excellent solvent resistance

We introduce a nanoporous membrane suitable for virus filtration with good dimensional stability under high pressures maintaining high selectivity. The membrane consists of a double layer: The upper layer is a nanoporous film with pore size of ∼17nm and a thickness of ∼160nm, which was prepared by polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) where PMMA block was removed by ultraviolet irradiation followed by rinsing with acetic acid. The nanoporous block copolymer film was combined with a conventional micro-filtration membrane to enhance mechanical strength. The membrane employed in this study did not show any damage or crack even at a pressure of 2 bar, while high selectivity was maintained for the filtration of human rhinovirus type 14 which has a diameter of ∼30 nm and is a major pathogen of the common cold in humans. Furthermore, due to crosslinked PS matrix during the UV irradiation, the nanoporous membrane showed excellent resistance to all organic solvents. This could be used under harsh filtration conditions such as high temperature and strong acidic (or basic) solution.