%0 journal article
%@ 0935-9648
%A Blagojevic, N.,Das, S.,Xie, J.,Dreyer, O.,Radjabian, M.,Held, M.,Abetz, V.,Müller, M.

%D 2024
%J Advanced Materials
%N 
%P 2404560 
%R doi:10.1002/adma.202404560
%T Toward Predicting the Formation of Integral-Asymmetric; Isoporous Diblock Copolymer Membranes
%U https://doi.org/10.1002/adma.202404560
 
%X The self-assembly and nonsolvent-induced phase separation (SNIPS) process of block copolymers and solvents enables the fabrication of integral-asymmetric, isoporous membranes. An isoporous top layer is formed by evaporation-induced self-assembly (EISA) and imparts selectivity for ultrafiltration of functional macromolecules or water purification. This selective layer is supported by a macroporous bottom structure that is formed by nonsolvent-induced phase separation (NIPS) providing mechanical stability. Thereby the permeability/selectivity tradeoff is optimized. The SNIPS fabrication involves various physical phenomena—e.g., evaporation, self-assembly, macrophase separation, vitrification – and multiple structural, thermodynamic, kinetic, and process parameters. Optimizing membrane properties and rationally designing fabrication processes is a challenge which particle simulation can significantly contribute to. Using large-scale particle simulations, it is observed that 1) a small incompatibility between matrix-forming block of the copolymer and nonsolvent, 2) a glassy arrest that occurs at a smaller polymer concentration, or 3) a higher dynamical contrast between polymer and solvent results in a finer, spongy substructure, whereas the opposite parameter choice gives rise to larger macropores with an elongated shape. These observations are confirmed by comparison to experiments on polystyrene (PS)-block-poly(4-vinylpyridine) (P4VP) diblock copolymer membranes, varying the chemical nature of the coagulant or the temperature of coagulation bath.