Sensing Properties of Metamaterials Utilized as Self-Cleaning Coating for Solar Mirrors

In this work the experimental activity conducted on self-cleaning sensitive metamaterial coatings for solar mirrors is described. The aim of the research activity is the modulation of solar mirrors wettability in order to reduce water consumption in ordinary cleaning operation and, consequently, maintenance costs, as well as the addition of sensoring properties to the mirrors for the remote acquisition of their performance. In particular, cermet metamaterials and hybrid polymers have been selected as matrices and doped with conductive particles. Considering that in the most part of solar mirrors architectures the external layer consists of an amphiphobic alumino-silicate, which has a wetting contact angle (WCA*) of around 50°, in this work different “silica-like” based coatings have been fabricated by means of sputtering deposition (for inorganic cermet metamaterials) and spraying (for polymers ) with the aim of obtaining a more hydrophobic behavior (WCA > 90° can halve the amount of water required for mirrors cleaning), preserving mirrors optical properties and exhibiting, at the same time, electrical properties suitable to sensoring purpose.