High performance and thermally stable PDMS pervaporation membranes prepared using a phenyl-containing tri-functional crosslinker for n-butanol recovery

Polydimethylsiloxane (PDMS) pervaporation membranes for n-butanol recovery were fabricated using various crosslinkers: a conventional tetra-functional crosslinker and tri-functional crosslinkers containing different organic (hexyl, cyclohexyl and phenyl) groups. Irrespective of the feed solution conditions, the membranes prepared using tri-functional crosslinkers exhibited a higher permeate flux than the membrane prepared using the tetra-functional crosslinker because their less crosslinked structures increased the free volume. Importantly, among the fabricated membranes, the membrane prepared using the phenyl-containing tri-functional crosslinker exhibited the highest separation factor with a remarkably high permeate flux even under high alcohol concentration and elevated temperature conditions. Its superior pervaporation performance was attributed to its highest hydrophobicity and excellent thermal stability, which are imparted by the phenyl group in the crosslinker, combined with the tri-functional structure of the crosslinker. Our proposed strategy provides an effective and facile method to fabricate high performance pervaporation membranes for alcohol recovery.