Chiral Smart Bionic Skin Film with Changeable Structural Colors and Tunable Luminescence by Polymer-Assisted Supramolecular Assembly of the Photonic Crystals

The biological skin system of advanced organisms can obtain various environmental stimuli to change skin colors by adjusting the micro-nano structure of the skin surface or by electroluminescence and photoluminescence. The assembly of biominetic skin materials with both changeable structural colors and tunable luminescence is a significant challenge in the fields of advanced materials and light science. This work describes a novel chiral smart bionic skin film with changeable structural colors, tunable luminescence by the polymer-assisted supra -molecular assembly of the photonic crystals. A smart nanodot based on the molecule with four-armed mimosa -like structure was assembled on the cellulose nanocrystals (CNC) photonic crystal. The chiral bionic skin film obtained had multi-channel fluorescence-emission, sensitive structural color stimulus responses to the light and humidity and the tunable chiral helical nematic domains. It demonstrates a series of the supramolecular in-teractions that trigger multiple intelligent signals, including the adjustable chiral pitch, photo-induced electron transfer (PET), intramolecular fluorescence resonance energy transfer (FRET), 7C -7C stacking and the changes of the hydrogen bonds. The photonic crystal skin materials with sensitive multi-signals intelligent responses as smart bionic skin have potential applications for the tissue engineering, 3D printing materials, bionic artificial skin materials, and optical devices.