Reversible thermochromic microencapsulated phase change materials for enhancing functionality of silicone rubber materials

The thermochromic phase change microcapsules (ETPCWs) are constructed by encapsulating ternary core composed of crystal violet lactone, bisphenol A and phase change wax into silica shell by in-situ condensation. It has good latent heat storage (∼130 J/g), high encapsulation efficiency (∼80%) and dual-output response (storage-release heat and thermochromic) produced by the solvent-modulated dissociation/aggregation mechanism. Upon heating, the ETPCWs exhibit light blue or even white, while return to dark blue when temperature decreases. Furthermore, thermochromic silicone rubber composites (TSRMs) are prepared by using ETPCWs as functional filler and silicone rubber as polymer matrix, which possess appropriate thermal regulation performance, improved thermal stability, favorable hydrophobicity, adjustable transparency and pleasurable mechanical properties. Especially, CIELAB color space values show that the TSRMs exhibit excellent thermochromic characteristics and outstanding recyclability. Therefore, this work provides a new idea for the development of functional phase change capsules, and the prepared thermochromic phase change microcapsule exhibits great application potential in security labels, intelligent electronic wearable devices as well as temperature sensors.