R10 3 SiO(R9 2 SiO)n SiR10 3 where, in the above formulae, R9 is a monovalent radical selected from the group consisting of alkyl, aryl, and fluorinated alkyl; each R10 is independently selected from the group consisting of R9, hydroxyl, and a hydrolyzable group, Y is an acryl functional radical bonded to silicon atom through silicon-carbon bond where the acryl function has the formula ##STR5## or