Waterborne superhydrophobic coatings for the conservation of the cultural heritage

Waterborne polysiloxane coatings can obtain superhydrophobic and water-repellent properties by embedding oxide nanoparticles into the organosilicon matrix during coating deposition. The nanoparticles induce surface roughness resulting to extreme wetting properties. This general strategy is demonstrated and implemented in this case study where a commercial water-based emulsion of silanes/siloxanes is mixed with silica nanoparticles (7 nm) and brushed on mortar, ceramic, and wood. These materials are found in monuments and outdoor objects of the cultural heritage, which are subjected to degradation by rainwater and humidity. Water drops on the produced polysiloxane–silica coatings correspond to large static contact angles (>150 degrees) and small sliding angles (