Materials Aspects of Solar Paint Coatings for Building Applications

This chapter consists of two parts. In the first one a brief historical overview of the development of solar paint coatings is given together with the basic principles that make paint coatings spectrally selective. Distinctive properties of Thickness Sensitive Spectrally Selective (TSSS) and Thickness Insensitive Spectrally Selective (TISS) are outlined and the use of the latter paint coatings as cool paints is proposed and demonstrated. Materials’ aspects of the colored cool TISS paint coatings are given by the description of cool pigments, metallic and metallized flake pigments and polymeric resin binders which are used for the production of solar paint coatings. Second part contains information about the chemistries of the paint production showing how to achieve with the help of dispersant molecules uniform distribution of the finely ground pigment particles in the polymeric resin binder. Intentionally, we focused on organo (silicon) i.e. silane dispersants because they enable the stabilization of many different nanoparticle systems and also commercial pigments. Basics of the sol-gel chemistry of silanes are given and the preparation of polyhedral oligomeric silsesquioxane (POSS) molecules is described and the dispersive effect of the latter on pigments demonstrated. The importance of the POSS molecules representing a new multifunctional nanocomposite materials is revealed by describing paints and lacquers with hydrophobic and oleophobic properties and the possibility to attain anti-soiling properties of cool paints is also discussed.

Keywords: Spectral selectivity, absorbers, building facades, paint formulation, lifetime prediction, cool paints, cool pigments, silan dispersant, polyhedral oligomeric silsesquioxanes, thermal emissivity, solar absorptivity, TISS, TSSS.