New fluorinated polysiloxanes containing an ester function in the spacer. I. Synthesis and characterization

Unsaturated perfluoroalkyl esters derived from undecylenic acid: CH2CH(CH2)8COOCH2CH2RF (with RFC6F13, 2a and RFC8F17, 2b) and C8F17(CH2)10COOCH2CHCH2, 2c were prepared with excellent yields. Their hydrosilylation by methylhydrodimethylsiloxane copolymers of various SiH contents gives new fluorinated polysiloxanes which were examined by 1H‐ and 13C‐NMR, GPC, differential scanning calorimetry, and optical polarizing microscopy. Polymers derived from compounds 2a and 2b exhibit mesomorphic structures.