Functional coatings on glass surfaces by the sol-gel process

Abstract

The wetting behavior and thereby the surface free energy of coating materials for glass surfaces is tailored by incorporation of fluorinated side chains in inorganic organic nanocomposites, known as ORMOCERS (ORganically MOdified CERamics), synthesised by the sol gel process. We investigate the influence depending on concentration and chain length of the fluorinated precursor. The transparent coatings (≈ 5 µm) show good abrasion resistance and a good adhesion on glass surfaces. The incorporation of only small amounts of perfluorinated chains with a length of 6 or 8 leads to an hydrophobic and oleophobic behavior of the coatings similar to perfluorinated organic polymers because of an enrichment of fluorine at the surface. On the other hand the incorporation of hydrophilic groupings (C-OH, tensides) leads to hydrophilic behavior of the surface.