Self?Assembled Nanorods and Microspheres for Functional Photonics: Retroreflector Meets Microlens Array

Patterned micro/nanomaterials display efficient light management capabilities owing to their control of propagation within multiscale periodic structures. Here a hierarchical photonic structure composed polystyrene microspheres and cholesteric assembly cellulose nanocrystals is described, acting as polarization-sensitive retroreflective coating microlens array. Micropatterned films are prepared by casting an aqueous nanocrystal suspension onto monolayer substrate through evaporation-assisted transfer imprinting lithography, integrating bulk matrix patterned surface. By directing at the as-assembled surface, enhanced structural color develops from circularly polarized retroreflection. Whereas when travelling across film, transparent layer forms into plano-convex converge transmitted focus plane reduce centimeter-scale illuminated image high-fidelity miniaturized replica. This simple method, combining self-assembly with expected pave way for designing custom-tailored optics novel functions.