A series of fluorosilicone (FLS) homopolymers with 4,4,5,5,6,6,7,7,8,8, 9,9,10,10,11,11,11-heptadecafluoroundecylmethylsiloxane [-C8F17CH2CH2CH2(CH3) SiO-; HDFUSiO] and copolymers based on dimethylsiloxane [-(CH3)(2)SiO-] were prepared by the hydrosilylation of 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-1-undecene (C8F17CH2CH=CH2) with poly(hydromethylsiloxane)s. Thermal characterization showed that the decomposition of fluoroalkyl side chains occurred at about 245 degreesC. Side-chain crystallization was observed for FLSs with more than 30 mol % HDFUSiO. The refractive index decreased with increasing HDFUSiO content. The dielectric constant increased with increasing HDFUSiO content. The liquid surface tension of the FLS containing 10 mol % HDFUSiO was as low as that of the highly fluorinated FLSs. FLSs with HDFUSiO and trichlorosilylethyl side chains (Cl3SiCH2CH2-) were also prepared so that their solid surface tension (surface free energy) could be measured. The surface free energy of these FLSs decreased with increasing Cl3SiCH2CH2- content, but the sliding angle of a water droplet and the contact-angle hysteresis adversely increased. (C) 2003 Wiley Periodicals, Inc.