Smart reversible thermochromic mortar for improvement of energy efficiency in buildings

A smart reversible thermochromic mortar based on ordinary white Portland cement and organic microencapsulated thermochromic pigments is presented in this work. Chemical and morphological composition of the mortar assures chemical stability and proper physical and organic activity of the pigments within the cementitious matrix. The optical properties of the mortar change with temperature at the transition value of the pigments (31 °C). For higher temperatures, the material shows a light colour and high reflectance in the visible range, while for lower temperatures it shows a dark grey colour associated to a low reflectance. Infrared spectroscopy and electron scanning microscopy results confirm the chemical and morphological stability of the microencapsulated pigments within mortar samples cured for 28 days. Finally, physic-mechanical properties of fresh and hardened mortar demonstrate the suitability of this innovative material as a dynamic building coating for improvement of energy efficiency.