Bioinspired Dual‐Mode Temporal Communication via Digitally Programmable Phase‐Change Materials

Abstract Switchable optical properties are essential for numerous technologies including communication, anticounterfeiting, camouflage, and imaging/sensing. Typically, the switching is enabled by applying external stimulation such as UV light for fluorescence detection. In contrast, ground squirrels utilize spontaneous live infrared emission for fencing off predators as a unique way of communication. Inspired by this, live evolution of both optical and thermal images for temporal communication in which time is the encoded information is demonstrated. This system is based on a digitally light‐cured polymeric phase‐change material for which the crystallization kinetics can be controlled in a pixelated manner. Consequently, live evolution in optical transparency during the crystallization process enables temporal optical communication. Additionally, by harnessing the dynamic evolution of the thermal enthalpy, multiple sets of time‐specific information can be reversibly retrieved as self‐evolving infrared thermal images. The versatility of this dual‐mode temporal system expands the scope for secured communication, with potential implications for various other areas including optics, thermal regulation, and 3D/4D printing.