Sol-gel hybrid coatings containing silica and a perfluoropolyether derivative with high resistance and anti-fouling properties in liquid media

Organic inorganic hybrid coatings were prepared using a commercial triethoxysilane α,ω substituted perfluoropolyether as organic phase in combination with tetraethyl orthosilicate (TEOS) as inorganic phase. The coatings were prepared by sol-gel synthesis of a silica coating in co-presence with the commercial polymer, and deposited on stainless steel substrates by dip-coating procedure. The interactions between the organic and the inorganic components were studied by means of X-ray photoelectron spectroscopy. The synergistic effect of the two opposite phases permitted to obtain hydrophobic coatings (contact angle CA of ∼140°) with high resistance against thermal or mechanical stresses induced in liquid media. The hybrid coatings thus obtained possess suitable properties for application as anti-fouling coatings in liquid environments. Specific tests performed in particulate fouling conditions confirmed the ability of the hybrid coatings to mitigate CaSO4 deposits formation, maintaining unaltered the CA value after exposition for 43 days to a flux of a CaSO4 solution at a flowrate of 0.15 m/s.