Ordered nanoporous membranes based on diblock copolymers with high chemical stability and tunable separation properties

Abstract

Block copolymers, having the ability to self-assemble into arrays of well-defined nanostructures, can be turned into thin films. Their application as membrane was so far strongly limited by the fact that these thin films have to be transferred manually onto a porous membrane support, or because of the very strict preparation conditions. A simple method is reported here to directly produce ordered nanoporous membranes on porous supports. Well-ordered membrane structures were prepared via a simple strategy exploiting blending of a block copolymer (PS-b-PEO) with a homopolymer (PAA), involving no thermal or solvent treatment. The membranes could be directly introduced on several types of porous membrane supports via straightforward spin or dip coating of very small amounts of polymer. Moreover, the permeability of the membranes could be readily tuned by removal of the PAA without changing membrane morphology. While already inherently stable in e.g. sodium hypochlorite solutions, the chemical stability of the membranes could be further enhanced via simple UV-radiation, clearly widening their potential application field.