Materials for intelligent sun protecting glazing

The aim of this review is to present the last 10 years of development in sun protection by use of electrochromic devices, thermotropic gels and polymer dispersed liquid crystalline systems. Furthermore, the properties of new lyotropic liquid crystalline and thermotropic hydrogels are discussed. Thermochromic hydrogels, which change their colour by changes in the temperature, also are presented. The relationship between gel composition, optical behaviour and thermodynamic properties as investigated by differential scanning calorimetry (DSC) is also demonstrated. (C) 2000 Elsevier Science B.V. All rights reserved.