Silanes which may be copolymerized include [R43(CH2)m]xR44 ySi(OR)z[(CH2)kCH???CH2] wherein each R43 is independently perfluoroalkyl optionally containing one or more ether groups; R44=is substituted hydrocarbyl or hydrocarbyl, m is an integer of 2 to 6, k is 0 or 1 (vinyl or allyl), x is 1, 2 or 3, y is 0, 1 or 2, and z is 0, 1 or 2, provided that x+y+z=3.