Thermochromic Insulation Materials for Thermal Sensing and Overheat Prewarning

The real-time monitoring and scientific prewarning of local overheating for electrical equipment and electronic devices are of great significance but remain challenging. Therefore, in this work, a temperature-responsive microcapsule is prepared to endow insulating materials with the ability to thermally sense external temperature fields. Specifically, in the microcapsule/epoxy composites, the epoxy resin served as the polymer matrix was doped with reversible thermochromic microcapsules, acting as a temperature indicator whose color transition temperature is centralized between 45 °C and 55 °C. The test results indicate that the color of the prepared composites can sensitively vary in response to the fluctuations in external ambient temperature, which was illustrated by the behavior of isothermal melting. Further analysis reveals that composites are able to precisely locate multiple tiny overheated areas and present remarkable thermal durability undergoing 480 h of aging at 70 °C. The thermochromic materials designed in this article provide a new technological route for large-scale thermal sensing applications of electrical equipment.