Rational Design of 3D Morphable Color‐shifting Mesosurfaces Using Bioinspired Janus Micro‐ and Nanolattices

Morphable 3D mesosurfaces with tunable optical properties present unique opportunities for adaptive, multifunctional systems such as next-generation displays, intelligent camouflage, and visual-based mechanical sensing. Directly embedding nanoscale optical features onto morphable, curved 3D mesosurfaces remains challenging, due to the extreme mismatch in length scales and material limitations. 3D assembly methods offer alternative routes to the fabrication of morphable 3D color-shifting mesosurfaces, but the synergetic design/control of visible optical performance and complex 3D shapes has rarely been explored. Inspired by the biological construction of hierarchical micro- and nanopores in diatom cell walls, novel design strategies of 3D morphable color-shifting mesosurfaces with rationally engineered Janus micro- and nanolattices are proposed. A double-sided patterning method, combining top-down lithography and nanomolding, enables precise integration of Janus lattices onto thin-film 2D precursor structures, which are then transformed into target 3D mesosurfaces through buckling-guided 3D assembly. Synergetic designs of micro- and nanolattice patterns allow the customization of 3D optical mesosurfaces with desired shapes and reflectance distributions, guided by a theoretical mechanics model and experimentally measured reflectance spectra. Leveraging angle-dependent reflectance, morphable ribbon-shaped surfaces whose color changes gradually during in-plane stretching and out-of-plane compression are demonstrated, suggesting potential applications in power-free, visual-based strain and pressure sensing.