Bioinspired Synergistic Fluorescence-Color-Switchable Polymeric Hydrogel Actuators.

Many living organisms have amazing control over their color, shape, and morphology for camouflage, communication, and even reproduction in response to interplay between environmental stimuli. Such interesting phenomena inspire scientists to develop smart soft actuators/robotics via integrating color-changing functionality based on polymer films or elastomers. However, there has been no significant progress in synergistic color-changing and shape-morphing capabilities of life-like material systems such as hydrogels. Herein, we reported a new class of bioinspired synergistic fluorescence-color-switchable polymeric hydrogel actuators based on supramolecular dynamic metal-ligand coordination. Artificial hydrogel apricot flowers and chameleons have been fabricated for the first time, in which simultaneous color-changing and shape-morphing behaviors are controlled by the subtle interplay between acidity/alkalinity, metal ions, and temperature. This work has made color-changeable soft machines accessible and is expected to hold wide potential applications in biomimetic soft robotics, biological sensors, and camouflage.