POLY[PARA-(1H,1H,2H,2H-PERFLUOROALKYLOXYDIMETHYLSILYL)STYRENES] AS MATERIALS FOR ETHANOL-PERMSELECTIVE MEMBRANES

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 (alpha(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 (alpha(EtOH) = 22.3, P = 2.06 x 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.