Bioinspired Trichromatic Photonic Skins for High-Resolution Underwater Motion Tracking

Incorporating magnetically responsive nanostructures into flexible elastomers enables the rapid construction of dynamically tunable photonic skins. However, existing systems fail to achieve pure-color-bending recognition due to monochromatic limitations. We present a chameleon-inspired trichromatic photonic skin (TPS) through the magnetic-field-guided assembly of Fe₃O₄@SiO₂ nanoclusters within polyacrylamide hydrogels to miniaturized sizes. The TPS uniquely decouples mechanical stimuli (stretching, pressure, and bending) into distinct structural color pixels via independent peak shifting in the reflection spectra, of which the precision surpasses conventional single-color systems. Moreover, mask-assisted ultraviolet light polymerization further enables programmable pixelation for underwater sensing and encryptions. This multiparameter responsiveness allows real-time optical tracking of underwater motions, including shark locomotion and finger articulation. Our strategy establishes a single-component paradigm for creating intelligent multichannel optical interfaces with fine color resolutions.