Formation of Nanoporous Membranes from Block Copolymer Solutions


The use of block copolymer membranes is of important interest in many applications. In order to fabricate a block copolymer membrane, different approaches have been used. Yang et al. prepared a block copolymer thin layer with hexagonally packed perpendicular oriented cylinders on a sacrificial silicon oxide layer from solution. After drying they transferred the block copolymer thin layer onto a microfiltration polysulfone membrane, which acts as a mechanically stable support and showed its potential for protein filtration.[1] A recently published approach consists of the preparation of a block copolymer membrane with an asymmetric morphology by combining the nonsolvent induced phase separation process and the self-assembly ability. The asymmetric structure consisted of a nonordered porous structure covered by a layer of ca. 250 nm thickness with hexagonally ordered cylindrical pores.[2] In the present work we study the direct casting of block copolymer solutions onto a mechanically stable porous material. By combining the self-assembly ability of block copolymers, the morphology generation in thin films and the porous material support, it is expected to obtain a continuous and uniform selective layer with slight interpenetration into the porous support that provides mechanical strength to the membrane. In this first work the aim is to obtain a continuous thin block copolymer layer on top of the substrate.
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