Three-Dimensional Electrochromic Soft Photonic Crystals Based on MXene-Integrated Blue Phase Liquid Crystals for Bioinspired Visible and Infrared Camouflage.

Developing bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene-integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof-of-concept pixelated devices that allow for pixel-controllable electrochromism are demonstrated. Furthermore, a free-standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid-IR emissivity of MXene nanomaterials.