Pervaporation membranes with POSS-reinforced polyether network via in-situ cationic photopolymerization for azeotropic organic solvent mixture separation

The primary challenge for pervaporation in organic solvent separation lies in the inherent trade-off between permeability and selectivity, along with swelling issues of traditional polymer membranes. While nanofillers offer a promising solution, achieving their interfacial compatibility and uniform dispersion within the polymer matrix remains the key to success. In this study, we fabricated a PTFE/Py(P-G) pervaporation membrane via cationic photopolymerization of epoxy-functionalized polyhedral oligomeric silsesquioxane (POSS) and glycidol for the separation of ethanol/n-hexane azeotrope. By chemically crosslinking POSS into the polymer network, we effectively addressed the issues of loading limitation and poor compatibility commonly encountered in nanofiller-based membranes. The constructed POSS-reinforced polyether network exhibited exceptional organic solvent resistance. Within this hybrid structure, POSS units provide selective transport pathways, while the polyether segments contribute to increased free volume and enhanced ethanol affinity. The optimized PTFE/Py(P-G)-0.45 membrane achieved a high separation factor of 225.07 for ethanol/n-hexane azeotrope, along with remarkable long-term operational stability in continuous testing. This work demonstrates the effectiveness of molecularly designed hybrid networks in advancing pervaporation membrane performance for challenging organic separations.