Fabrication And Properties Of Wettability Patterned Colloidal Photonic Crystals

Structural color has attracted research attention at home and abroad as a common information communication medium in nature because of its bright rainbow color and excellent performance.Responsive photonic crystals are widely used in many fields because of their simple preparation and rapid response.This paper designed a wettability patterned photonic crystal film with planar defects.The change of its structural color was controlled by introducing optical properties and wetting response.The finite element analysis software COMSOL Multiphysics was used in this paper to simulate and calculate the influence of crystal parameters under different structures on the structure color.A wettability patterned photonic crystals film with planar defects was prepared based on the research results.The film’s optical properties were characterized and analyzed,and the application prospect of the structural color film was discussed.Firstly,the basic principles and characteristics of photonic crystals were introduced.The basic principle of photonic bandgap on structural color and the effect of photon localization on structural color were analyzed.Secondly,the basic principle and process of the finite element analysis method were introduced,and the using process of the wave optics module in the COMSOL Multiphysics software was described,which laid the foundation for the following structural design and simulation.Thirdly,the wave optics module of COMSOL multiphysics software was used to simulate and calculate the feasibility of three-dimensional photonic bandgap structure and photonic crystal structure with planar defects.For the 3-D photonic bandgap structure,the effects in photonic crystals material,particle size,and structure were simulated and analyzed.The effects of different defect structures,defect thicknesses,and crystal models on the reflection spectrum were simulated and analyzed.At the same time,based on the simulation data,a wettability patterned photonic crystal film with planar defects was designed and simulated,and the performance of the composite film in anti-counterfeiting was analyzed.Finally,the wettability patterned photonic crystals film with planar defects was prepared based on the simulation data.It has a wettability response to organic solvents like ethanol,which can realize the display and hide of the underlying pattern;simultaneously,the new anti-counterfeiting performance is provided by the unique double-peak reflection spectrum of the underlying pattern.The repeated wetting experiments confirmed the response cycle performance of the composite film,and it is expected to be widely used in the field of anti-counterfeiting and information encryption.