Surface properties and anti-fouling assessment of coatings obtained from perfluoropolyethers and ceramic oxides nanopowders deposited on stainless steel

Multilayer coatings were obtained on stainless steel surfaces by combining a commercial a,o-functionalized perfluoropolyether film with a film of ceramic oxide nanopowders, namely, TiO2 or ZrO2. Ceramic oxides were impregnated with siloxanes in order to improve their hydrophobic behavior and favor the adhesion on metal substrates. The coatings obtained had homogeneous morphology and thickness of about 25 mm. A possible application of low energy surface coatings is fouling mitigation. Thus, the chemical and mechanical stability of the multilayer coatings was assessed in liquid environments and compared to the one of simple perfluoropolyether coatings. Moreover, particulate fouling (due to CaSO4 deposition) was investigated on perfluoropolyethers coatings and multilayer coatings. Results demonstrated good resistance of the multi-layer coatings toward aggressive chemicals and water erosion. With respect to an uncoated stainless steel surface, the CaSO4 particles adhesion on the coated surfaces was estimated 70–90% lower, in the fouling conditions adopted.