NEW FLUORINATED POLYSILOXANES CONTAINING AN ESTER FUNCTION IN THE SPACER .2. SURFACE-TENSION STUDIES

The surface tensions of fluorinated polysiloxanes prepared by hydrosil ylation of unsaturated perfluoroalkyl esters derived from undecylenic acid [CH2=CH-(CH2)(8)-COO-CH2-CH2-R(F), with R(F)=C6F13, C8F17, and C8 F17-(CH2)(10)COO-CH2-CH2-CH=CH2] by methylhydrodimethylsiloxane copoly mers of various Si-H contents have been measured. The critical surface tensions, gamma(c), and the solid surface tensions, gamma(S)(D), were deduced from n-alkane and water contact angle data. They decrease as the perfluoroalkyl graft content of the copolymers increases. Some of them, which are in the range of the lowest surface tension fluoro poly mers known, are observed when the fluorinated segments are self-organi zed at the interface, i.e. when the polymers are mesomorphous or cryst alline at room temperature.