Poly[ p-1H,1H,2H,2H-perfluoroalkyloxydimethylsilyl)styrenes] as materials for ethanol-permselective membranes

Abstract

Several p-(1H,1H,2H,2H-perfluoroalkyloxydimethylsilyl)styrenes having perfluoroalkyl groups with different chain lengths were synthesized and polymerized. The polydimethylsiloxane-based blend membranes which contained a very small amount (1.0 wt%) of poly[ p-(1H,1H,2H,2H-perfluoroalkyloxydimethylsilyl)styrene] had good ethanol permselectivity. All of their separation factors ( α EtOH) and permeation rates ( P) were higher than those of polydimethylsiloxane. In particular, poly[ p-(1H,1H,2H,2H-perfluorohexyloxydimethylsilyl)styrene] showed the best performance ( α EtOH = 22.3, P = 2.06 × 10 −2 g m m −2 h −1). This was attributed to the characteristics of the fluorine-containing polymers which were accumulated at the membrane surface.