Gas permeation properties of poly(1,1′-dihydroperfluorooctyl acrylate), poly(1,1′-dihydroperfluorooctyl methacrylate), and poly(styrene)-b-poly(1,1′-dihydroperfluorooctyl acrylate) block copolymers

Abstract

The permeabilities of rubbery poly(1,1′-dihydroperfluorooctyl acrylate) (PFOA), glassy poly(1,1′-dihydroperfluorooctyl methacrylate) (PFOMA), and poly(styrene)-b-poly(1,1′-dihydroperfluorooctyl acrylate) (PS-b-PFOA) diblock copolymers to N2, O2, H2, CH4, C2H6, and CO2 at 446 kPa and to C3H8 at 308 kPa are reported as a function of temperature. In general, PFOMA has lower fractional free volume, smaller gas permeability coefficients, and larger activation energies of permeation than PFOA, consistent with the more restricted long-range segmental mobility of PFOMA. The PS-b-PFOA copolymers exhibit complex microphase-separated morphologies, and their gas permeability coefficients are intermediate between those of glassy PS and rubbery PFOA, decreasing in magnitude with increasing PS content.