Organic solvent resistant membranes made from a cross-linked functionalized polymer with intrinsic microporosity (PIM) containing thioamide groups

A nanometric functionalized polymer of intrinsic microporosity (PIM), i.e., thioamide-PIM-1 (TPIM), has been synthesized and applied for dyes removal from ethanol and acetone solutions for the first time. The presence of thioamide groups in TPIM provides the anchor to further cross-link the polymer with trimesoyl chloride (TMC) so that the resultant membranes not only have a tight pore size (i.e., small free volume), but also have better chemical stability and rejection. The organic solvent nanofiltration (OSN) membranes were prepared by depositing a thin TPIM layer on top of cross-linked P84 polyimide substrates by means of spin coating. With the novel TMC modification, the resultant multilayer membranes have a rejection reaching 90% to remazol brilliant blue R (Mw: 627 g mol(-1)) with a pure ethanol permeance of 3.4 Lm(-2) bar(-1) h(-1). It also has an impressively high acetone permeance of 12.42 Lm(-2) bar(-1) h(-1) with a rejection of 97% to rose bengal (Mw: 974 Da). This study may open up new insights and strategies to modify other PIMs for OSN applications.