Effect of crosslinker 3-methacryloxypropylmethyldimethoxysilane on UV-crosslinked PDMS-PTFPMS block copolymer membranes for ethanol pervaporation

Abstract Crosslinker is a vital factor for the preparation of polymeric membranes, which has a substantial effect not only on the membrane-forming process, but also on the membrane structure as well as separation performance. However, little attention has been paid on UV-crosslinked membrane for organics pervaporation. In this work, the effect of crosslinker 3-methacryloxypropylmethyldimethoxysilane (KH571) on (1) the UV-crosslinking kinetics was characterized by real-time infrared spectroscopy and photo-rheology, (2) the membrane structure was characterized by crosslinking density, and (3) separation performance was evaluated by ethanol pervaporation. Moreover, the conventional polydimethylsiloxane (PDMS) was replaced by polydimethylsiloxane-poly[(3,3,3-trifluoropropyl)methylsiloxane] (PDMS-PTFPMS) block copolymer, where the strong C-F bond contributes to enhance membrane hydrophobicity. Results show an ultrafast membrane-forming process (30-50 s) for all coating solution systems and an outstanding separation performance, including 11.3 of ethanol separation factor and 1149 g m-2 h-1 of total flux for pervaporation recovery of 5 wt% ethanol/water solution at 60 °C.