Fouling of surfaces caused by pollution, contamination, humidity and microorganisms is one of the major sources of the degradation of mineral and composite materials. The inhibition of foulant growth is essential for the prevention of different kinds of damage, ranging from aesthetic, mechanical and chemical, to risks concerning human and environmental health. This study proposes a new approach for the development of a transparent preservative material with water-repellent and biocide attributes through the use of a sol-gel method. It was found that Si–O–Si dense networks can effectively grow into the micro-pores of mineral and cellulose-based materials, promoting self-cleaning properties as well as sufficient protection against bio-fouling.

Sol-gel is a widely applied method for the development of hydrophobic anti-soiling coatings. Most of them however suffer from serious drawbacks which restrict their generic applicability, especially on surfaces with limited number of hydroxyl groups. This study aims to propose a facile and straightforward strategy for the development of an "one-fits-all" anti-soiling coating with strong adhesion to a variety of hard, non-absorbent surfaces. The structure of the proposed composition is based on a two-component coating system consisting of an organopolysilazane primer and an alkoxysilane topcoat, based on a quaternarized ammonium silane. Morphology and microstructure were systematically studied, while hydrophobicity, adhesion, stability, abrasion and chemical resistance were determined on aluminum and PC substrates. The anti-soiling behavior of the proposed coating system was also evaluated. It was found that the polysilazane primer provided mechanical and chemical robustness regardless of substrate type, while the quaternarized silane offered pronounced easy-to-clean and anti-static attributes. The combination of such attributes within a single sol-gel coating system is highly beneficial for numerous applications.