Visible-light-programmed patterning in dynamically bonded cholesteric liquid crystal elastomer.

Optical properties of cholesteric liquid crystal elastomers (CLCEs) can be tuned by an external field, however, it will spontaneously restore to the original state after the field is removed. Here, we introduce diselenide dynamic covalent bonds (DCBs) into CLCEs, whose optical properties can be reversibly and precisely tuned under the combined action of force and light. The tuned optical properties will be written into and remembered by the CLCEs, thus a programming effect is achieved. The prepared dynamical diselenide bonded CLCE films have the typical reversibly mechanochromism property, and high-resolution colourful patterning can be programmed by adjusting exposure time and intensity of masked visible-light under different tensile or compressive strain states. The DCB-CLCEs combine the novel anisotropy of CLCEs and the dynamic chain exchangeable ability of DCBs, which endows the materials with reprogrammable optical properties. We demonstrate a simple strategy of writing naked-eye high-resolution colourful patterning into a film with mechanochromism property by thermal or visible-light, it shows great potential in display devices, anticounterfeiting labels, sensors, optical films and smart materials.