Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

摘要: Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These ultrastructures are responsible for structural colors observed in some beetles plants that can dynamically respond to external conditions, humidity temperature. In this paper, the formation undulations investigated through interaction anisotropic interfacial tension, swelling hydration, capillarity at free surfaces. Focusing on cellulosic cholesteric crystal (CCLC) material model, generalized shape equation interfaces using Cahn-Hoffman vector Rapini-Papoular anchoring energy applied analyze periodic plant-based plywood surfaces with water-induced pitch gradients. Scaling used derive explicit relations between undulations’ amplitude expressed a function strength spatially varying pitch. The optical responses nano-structured studied finite difference time domain simulations indicating CCLC reflect light wavelength higher than CCLC’s constant This color change controlled by gradient hydration. All these findings provide foundation understand phenomena nature design sensor devices.