Surface properties of fluorinated hybrid coatings

A commercial perfluoropolyether containing alkoxysilane functionalities was employed to prepare organic-inorganic hybrid coatings by using the sol-gel process in the presence of tetraethoxysilane. Contact angle analysis revealed a strong hydrophobic and oleophobic character of the coatings almost independently from the molecular weight of the starting fluorinated oligomer. Surface tension values were in the range of 14-16 mN/m, suggesting a preferential segregation of fluorinated segments onto the surface of the coating. Atomic force microscopy showed the presence very smooth surfaces permitting to neglect the contribution of the surface roughness to wettability. Friction coefficient values were markedly lower with respect to the value of uncoated glass substrate. (c) 2006 Wiley Periodicals, Inc.