Copolymerizations of 1,1-dihydroperfluorooctyl methacrylate (FOMA; M-1) and methacryloxypropyl-terminated polydimethylsiloxane [M-PDMS (M-n = 5.9 K); M-2] and homopolymerization of M-PDMS in supercritical CO2 are described. The homopolymerization of M-PDMS proceeded homogeneously without difficulty to produce oligomers (M-n = 30 K), The copolymerizations of FOMA and M-PDMS also proceeded homogeneously over a wide monomer feed ratio, The ratio of M-PDMS incorporated into the copolymer obtained was almost equal to the monomer feed ratio even up to the high conversion. The reactivity ratio r(1) was determined to be 1.66. DSC examination of the copolymers indicated a microphase-separated morphology consisting of poly-FOMA (PFOMA) and PDMS domains for all copolymer compositions.