sioh that is formed by hydrolysis of the alkoxy groups present on the silane the tbd sioh groups tend to react with the surface and bind the silanes to the surface it is believed by the inventor that even though the prime mode of coupling to the surface system is by the route described above it is also believed by the inventor that the alkoxy groups on the silicon atom may also participate in their own right to bind to the surface preferred for this invention is a reactive surface containing some small amount of water by 34 reactive 34 it is meant that the surface must contain some groups which will react with some of the silanols generated by hydrolysis of the silanes of this invention r in the silanes of this invention are alkyl groups of 1 to 4 carbon atoms thus useful as r in this invention are the methyl ethyl propyl and butyl radicals in the above formulas ro can also be r r can also be hydrogen thus indicating the silanol form i e the hydrolyzate the value of a is 0 1 or 2 and r 39 is a methyl or ethyl radical r 34 for purposes of this invention is an alkylene group of 1 to 4 carbon atoms thus r 34 can be alkylene groups such as methylene ethylene propylene and butylene r 39 34 r 34 34 and r v are each independently selected from a group which consists of alkyl radicals of 1 to 18 carbons ch 2 c 6 h 5 ch 2 ch.