Artificial Chameleon Skin with Super-Sensitive Thermal and Mechanochromic Response

Abstract

Both the nonclose-packed structure and the large refractive index contrast of guanine nanocrystals and cytosols in iridophores play a vital role in the dynamic camouflage of chameleons, including the bright skin color and color tuning sensitivity to external stimulus. Here, the nonclose-packed photonic crystals consisting of ZnS nanospheres and polymers, which have similar refractive indices with guanine nanocrystals and cytosols, respectively, are constructed by a twostep filling strategy. ZnS@SiO 2 nanospheres are self-assembled to build intermediate close-packed photonic crystals followed by filling polymers in their interstices. The nonclose-packed photonic crystal is successfully achieved when the silica portion is etched by HF solution and refilled by polymers. Excitingly, the stimulus response of the designed photonic crystal is as sensitive as the skin of chameleons due to the similar contrast of refractive indices and nonclose-packed structure. The reflection peak of the structure can blue-shift more than 200 nm as the temperature increases from 30 to 55 °C or under 20% compressional strain. This work not only builds the nonclose-packed photonic crystals by introducing a two-step filling strategy but also proves that high refractive contrast in photonic crystals is an effective strategy to achieve ultrasensitivity, which is highly desirable for various applications.

Reconfigurable Mechanochromic Patterns into Chameleon-Inspired Photonic Papers

“…The 2D and 3D angleresolved reflection spectra (Figure S1(c)) of the PC paper show that its reflection wavelength blue shifts from 480 to 393 nm and the corresponding color changes from blue to purple (Figure S1(d)) when the incident and detection angle decrease from 0 to 60 °simultaneously, further verifying the long-range ordered structures of the PC paper. These results firmly demonstrated that the PC paper possesses highly ordered and nonclosely packed structures similar to those of chameleon skins [71][72][73][74].…”

Biomimetic Chromotropic Photonic‐Ionic Skin with Robust Resilience, Adhesion, and Stability

“…[19] The structural color, generated by the interaction between light and ordered micro-nano structures, has the advantages of strong stability, continuous change, and ease of regulation. [22][23][24][25] Thereby, combining structural color with ionogels provides a promising strategy to construct I-skins with synchronous electrical and optical signals, in which the ionic signal offers precise sensing capability and the color change provides visual information, allowing for higher-level applications including multifunctional sensing, visualized dynamic displays, and direct intelligent interactions with users. However, the relevant research is still in its infancy and rarely reported.…”

Freeze-derived heterogeneous structural color films

“…Among them, the self-assembled colloidal crystals (CCs) have offered unprecedented opportunities, because of their cheap cost, facile preparation procedures, the comparative simplicity of scaling up, and flexibility of building complicated nanometer-precision architectures 14 , 15 . In particular, the non-close-packed CCs formed by the charge repulsion of highly charged nanoparticles are attracting great interest for their relatively simple fabrication and flexible color adjustment 16 . Benefitting from these advantages, a variety of functional structurally colored materials have been fabricated for displaying 17 , anti-counterfeiting 18 , coding 19 , 20 , etc 21 .…”