Photodegradation Studies of Pristine and Microencapsulated Thermochromic Coatings for Energy Savings in Outdoor Applications

Organic and polymer encapsulated thermochromic materials have potential use as energy savers in building envelopes, due to the fact their color chromatic behavior changes with temperature. External stimuli, such as solar radiation, often cause degradation in the physicochemical characteristics that impact their optical performance in real-time outdoor applications. The off-the-shelf polymeric encapsulated and three-component thermochromic dyes blended in a sodium silicate binder were prepared as coating materials on glass substrates using a dye-casting process with a film thickness of approximately 300 micrometers. These films have been systematically exposed to extended simulated sunlight environments at ambient conditions. The optical characteristics (UV-Vis absorption and transmission) were evaluated and compared with those of the pristine samples for photodegradation and related processes. We have also attempted to microencapsulate these thermochromic dyes for possible degradation mitigation, these results will also be presented and discussed in this study.