A Stable and Self‐Healing Thermochromic Polymer Coating for All Weather Thermal Regulation

Abstract Energy‐free thermal regulation is in great demand nowadays. Thermochromic materials are widely explored and used in smart windows. However, most thermochromic materials have fixed transition temperature and still suffer from poor stability. To overcome this challenge, a thermochromic polymer coating based on ion–dipole interaction with switchable transition temperature, high stability toward several harsh environments, self‐healing, and radiative cooling property is developed. It can continuously tune from transparent to opaque according to the temperature change. The lower critical transition temperature can be tuned from 33 to 43 °C by simply adjusting the composition of ionic liquids. Owing to the fluorine polymer backbone and dynamic ion–dipole interactions, it can also keep stable in aquatic, −20 °C, and 70 °C environments and self‐heal upon damage thus prolonging its working life for real applications.