Multiscale shape-memory effects in a dynamic polymer network for synchronous changes in color and shape

Abstract Chameleons and octopuses can escape predators because of their rapid movements, but, in addition, they can change their skin color in response to external stimuli or threats. To date, various smart materials to achieve shape or color changes have been prepared, and the realization of a single responsive behavior in one material is facile, but the development of multi-responsive materials without inter-response interference is challenging. Herein, we report a facile strategy to prepare materials having both shape and color memory by exploiting the shape-memory effect (SME) of a poly(e-caprolactone) (PCL)-based dynamic network programmed in specific shapes at both the macroscale and microscale. In detail, we used low-cost commercial recordable compact disks as the initial model of a photonic grating nanostructure and imprinted this on the PCL-based network via nanoimprinting and plastic reconfiguration, enabling both temporary and permanent shaping. Controlled by a single molecular stimulus (that is, the switch), the macroscale and microscale shapes recovered synchronously, and the microscale features are manifested as color changes, which we denote “color memory.” Thus, by utilizing the SME of our PCL-based material, bionic models capable of synchronous changes in color and shape on heating were prepared. In addition, using the surface-patterning technique, shape-memory materials having potential for information encryption and transfer platforms were also prepared. The results of this work will expand the use of shape-memory materials to the field of functional memory materials.