Solvent transport behavior in polymer membranes with intrinsic microporosity for organic solvent reverse osmosis

Abstract Organic solvent reverse osmosis (OSRO) is an emerging and promising technology for the separation of organic mixtures, which is realized by differential transport rates of organics through polymer membranes. However, the solvent transport characteristics and separation mechanism within OSRO systems remain unclear. Herein, we investigate the solvent transport behavior in polymer membranes with intrinsic microporosity by combining nonequilibrium molecular dynamics simulations with solvent permeation examinations. The results indicate that organic molecules permeate through the micropores in a clustered state driven by both pressure and concentration gradients. The selectivity of solvents is co‐determined by their sorption and diffusion in the swollen polymer membranes with a microporous character. The sorption selectivity is predominant in the overall selectivity toward polar ethyl ether/n‐butanol separation, whereas diffusion selectivity is more critical in nonpolar 1,3,5‐triisopropylbenzene/toluene separation. Generally, this work provides valuable insights into the development of next‐generation OSRO membranes for solvent separation.