Three different poly(imide-siloxane)s (PIS) containing rigid imide groups were synthesized by the reaction of amine end-capped imides to the siloxane backbone. These highly soluble amine terminated imides were synthesized by reacting fluorinated anhydride and three different amines (DDBP, DDM, DBP). The imides were grafted to the siloxane backbone by the epoxy group cleavage. All the polymers were obtained in quantitative yields with the inherent viscosities ranging from 0.32 to 0.45 dL/g. The polymers were characterized by FTIR, H-1 and C-13 NMR, and their thermal properties were studied. The DSC results showed two distinct glass transition temperatures demonstrating the existence of phase separation between the hard imide and soft siloxane groups. Polymeric membranes were prepared employing the coupling reaction between PIS and the polydimethylsiloxane matrix by varying the amount of incorporation of PIS. The membranes showed a high tensile strength of 82 MPa. The contribution of polar and dispersion component towards the total surface energy was studied by the contact angle measurements, and a reduction in surface tension of 15 mN/m was achieved with the fluorine containing PIS membrane. The study of the surface morphology was studied which confirmed the existence of phase separation in these systems. (c) 2008 Wiley Periodicals, Inc.