Bioinspired Artificial Photonic Nanocrystal Skin with High Sensitivity and Mechanical Color Change Properties for Camouflage and Visual Transmission

In order to form and regulate skin color throughout the entire visible range, chameleons use a non-close-packed arranged guanine nanocrystals in iris cells. Inspired by chameleons, PS@SiO2 particles are embedded particles in poly(ethylene glycol) phenyl ether acrylate (PEGPEA) to prepare photonic crystal thin films. Photonic crystal films have bright structural color (reflectivity >60%), high tensile strain (ε = 70%), high sensitivity (2.16 nm/%–1), a fast response time (1.9 nm/ms), and a wide tuning range of reflection wavelength (Δλ = 152 nm). The unique core–shell structure of PS@SiO2 microspheres has elasticity and stretchability. Polystyrene (PS) improves the refractive index difference between the nanometer microspheres and the elastomer matrix, making the structure color of the photonic crystal film brighter. Nondense arrays can ignore particle rearrangement under strain, making the mechanical discoloration process of thin films completely reversible. Based on these characteristics, this crystal thin film is used as a wearable sensor for the human body, which can report various actions by outputting different colors during the change process. Meanwhile, simple manufacturing processes have the potential to achieve large-scale production. So the crystal thin film has certain practical value in visual sensing, display, and anticounterfeiting.