Coloured patterns based on bioinspired photonic crystals for mechanocromic applications

Abstract

Photonic Crystals (PCs) are periodically organized dielectric nanomaterials that have a Photonic Band Gap (PBG) superimposed on the visible light regime. The simplest strategy for preparing PCs is the self-organization of spherical monodisperse nanoparticles via sedimentation of colloidal suspensions. Despite having vivid structural colors, this class of materials is fragile, and only flat films can be produced with natural sedimentation. In this project, we will develop a methodology to create arbitrary patterns, with personalized geometries obtained by direct ink writing with photocurable PUA resin on PC films. These films will be prepared by sedimentation of Polystyrene (PS), Poly(Methyl Methacrylate) (PMMA) and Poly (Ethyl Acrylate) (PEA) on an elastane substrate. The geometries must have mechanical stability and elasticity for mechanochromatic applications, and calibration curves will be obtained to estimate the degree of deformation with changes in the reflected color. The preparation of arbitrary standards expands the applicability of mechanochromatic materials that, until today, are mostly used in optical sensors to prevent damage to structures. Once responsive to mechanical stimuli, arbitrary standards can be used in optical sensors in the health sector and for printing mechanochromatic patterns for the fashion industry. (AU)