An oligomer of the formula: [R3SiO???]m[O???Si(R2)O???]n[SiO{fraction (3/2)}R]o[SiO{fraction (4/2)}]p???(I) wherein each R is selected individually from the group consisting of R1, ???OR2 and ???OR3; each R1 is independently a substituted or unsubstituted hydrocarbon group; each R2 is a C1-C6 alkyl group or an acyl group; and each R3 is a independently an alkyl or alkenyl group having at least 8 c