Improvement of the thermal efficiency of organic roof-coatings through design aimed at increasing the durability of thermochromic pigments

This work aims to improve the thermal efficiency of roof-coatings, by appropriate design of the samples. The pigments that provide thermochromic features to organic coatings, in fact, are susceptible to rapid physical-chemical degradation when exposed to atmospheric agents. Consequently, the study evaluated the effect of an additional top-layer with the task of increasing the durability and thermochromic efficiency of the pigments. The thermochromic pigment was analyzed by colorimetric analysis, infrared spectroscopy and optical and scanning electron microscope observations, while their thermochromic efficiency was evaluated exposing them to several thermal cycles. The protective properties of the coatings were assessed by electrochemical measurements, while their durability was investigated by different accelerated degradation tests. Finally, the thermal properties of the coatings were studied as a function of the degradation of the sample, to evaluate their thermochromic efficiency over time. This work demonstrates that the durability of the pigment, and consequently the thermochromic features of the coating, can be improved by applying an additional protective layer to the sample. Thus, this type of sample can be employed as roof-coating, with high long-term thermochromic efficiency.