Patent ID: 7641957

Claim:
A method of improving the surface smoothness of a polymeric substrate, comprising disposing a coating layer on a surface of the polymeric substrate by a process comprising applying to a surface of the polymeric substrate a coating composition comprising: (a) from about 5 to about 50 weight percent solids, the solids comprising from about 10 to about 70 weight percent silica and from about 90 to about 30 weight percent of a partially polymerized organic silanol of the general formula RSi(OH) 3 , wherein R is selected from methyl and up to about 40% of the R groups are a group selected from the group consisting of vinyl, phenyl, gamma-glycidoxypropyl, and gamma-methacryloxypropyl, and (b) from about 95 to about 50 weight percent solvent, the solvent comprising from about 10 to about 90 weight percent water and from about 90 to about 10 weight percent lower aliphatic alcohol, wherein the coating composition has a pH of from about 3.0 to about 8.0 and wherein a surface of said coating layer exhibits an Ra value of less than 0.6 nm, and/or an Rq value of less than 0.8 nm.