Asymmetric superstructure formed in a block copolymer via phase separation

Abstract

Self-assembly of amphiphilic block copolymers into well-ordered structures has attracted significant interest over the past decade. An especially attractive application of block-copolymer self-assembly is the formation of isoporous membranes. A major problem in this process is the lack of sufficient long-range order and the difficulty of up-scaling due to the time-consuming preparation steps. Here, we report an innovative and simple method to prepare isoporous membranes with nanometre-sized pores. The combination of the industrially well-established membrane formation method by non-solvent-induced phase separation with the self-assembly of a block copolymer is demonstrated. The result is the creation of an integral asymmetric membrane of a block copolymer with a highly ordered thin layer on top of a non-ordered sponge-like layer. This straightforward and very fast one-step procedure for membrane formation is reported for the first time. The developed membrane has the potential for highly selective separation.

Block Copolymer Membranes from Polystyrene-b-poly(solketal methacrylate) (PS-b-PSMA) and Amphiphilic Polystyrene-b-poly(glyceryl methacrylate) (PS-b-PGMA)

“…Later, the combination of the self-assembly of block copolymers and non-solvent induced phase separation (SNIPS) process allowed the preparation of isoporous membranes with high porosity and sharp molecular weight cut-off. In 2007, the first isoporous block copolymer membrane was reported to be cast from polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) by utilizing the diblock copolymer self-assembly and non-solvent induced phase inversion process (SNIPS) [11]. Later on it was shown that different additives can support the membrane formation [12][13][14].…”

Replication of flexible polymer membranes with geometry-controllable nano-apertures via a hierarchical mould-based dewetting

“…Such a thin SiN x membrane is known to be complicated and expensive to fabricate, and fragile under mechanical contact or moisture at ambient conditions. In parallel, a template-based bottom-up method is useful to create a free-standing membrane with nanoapertures integrated on a geometrical support by utilizing selfassembly of nano-particles 22 or block copolymers 23 . The ability to control the aperture shape or dimension, however, is potentially limited, restricting the widespread use of such a templatemediated approach.…”

Ferrocene-Modified Block Copolymers for the Preparation of Smart Porous Membranes

“…In the last decade, functional block copolymer filtration membranes attracted enormous attention because of their isoporous surface structure and capability for responsiveness stimulated by external triggers [34][35][36][37][38][39][40][41]. The most prominent and first block copolymer in this field is polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), which revealed tremendous potential for water purification and separation processes [42][43][44][45][46]. Quite recently, we reported on the preparation of the amphiphilic block copolymer polystyrene-block-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) for the formation of integral asymmetric porous membranes featuring a high water flux [47].…”