Hydrophobic and superhydrophobic coatings for limestone and marble conservation

Atmospheric pollution is mainly responsible for carbonate stones (limestone and marble) deterioration. Traditionally polymeric resins, acrylic and vinyl polymers, organosilicone compounds, and fluorinated film-forming agents have been applied to stone monuments as protective hydrophobic coatings against deterioration. In the last few years, nanomaterials (nano-oxides) have been frequently applied for restoration and conservation of works of art. Hybrid coatings have been realized using nanoparticles (oxides) mixed with commercial resins leading to superhydrophobic properties. In order to evaluate the stability of the applied coatings toward degradation induced by solar radiation and interaction with the atmospheric pollution, accelerated aging tests under UV irradiation and exposure to a typical polluted urban environment have been conducted.