Brush‐Paintable, Temperature and Light Responsive Triple Shape‐Memory Photonic Coatings Based on Micrometer‐Sized Cholesteric Liquid Crystal Polymer Particles

In this work, light and temperature responsive, brush‐painted photonic coatings exhibiting three different colored and surface topographical states are reported. The different states arise from the use of cholesteric liquid‐crystalline micrometer‐sized polymer particles as shape‐memory photonic pigments that are dispersed in a shape‐memory binder. The first temporal state is induced by compressing the photonic particles at high temperature, resulting in blueshift of the structural color. The second temporal state is obtained by embossing a diffractive grating on the surface at an intermediate temperature leading to a relief topography and a rainbow optical effect. Both optical and surface topographical changes coexist and are stable at room temperature until they are reverted independently either by heating or locally by light illumination. Multicolored paints that reflect selectively left‐handed or right‐handed polarized light are developed to create arbitrary polarization‐dependent multicolor and topographical brush‐painted patterns. These temperature and light responsive triple shape‐memory photonic paints have potential applications as battery‐free optical sensors, responsive decoration, and smart adhesives. Brush‐paintable, light and temperature responsive triple shape‐memory photonic coatings are fabricated by using cholesteric liquid‐crystalline particles as shape‐memory pigments dispersed in a shape‐memory binder. These easy‐to‐apply coatings exhibit irreversible optical and surface topographical changes that can be reverted independently either by direct heating or locally by light illumination. Such coatings find applications in battery‐free optical sensors and responsive decoration.