Thermotropic materials for adaptive solar control

Thermotropic materials offer an immense potential in adaptive solar control. They combine specific optical properties like absorbance and reflection, and high stability against solar radiation and heat with technology compatible processing capacities. Therefore, they represent perfect energy efficient materials. In detail, polymer blends, polymer-based hydrogels, casting resins, and thermoplastic films with a reversible temperature-dependent switching behavior have been investigated. Here a comparative evaluation of the different concepts with a view to their application in adaptive solar control is presented. Own current results exploit the well-known phase change materials and describe its use for adaptive solar control with extruded films or highly stable casting resins with thermotropic properties. Therewith, the status has changed from diffuse sunblind systems to intrinsic solar energy reflecting materials and a first smart window system based on phase change materials has now commercialized [1]. In summary: It is amazing that the solar energy itself is used as a promoter against solar heat.