Optimization on structure and process parameters of stretchable photonic crystal based on polychromatic sets for mechanochromism

Stretchable photonic crystals (SPCs) can regulate the structural color by deformation causing the variation of the lattice constant, which endows it with broad prospects in the fields of smart wear, flexible display, and dynamic camouflage, etc. The reasonable determination of the structure and process parameters of SPCs is crucial for their mechanochromic properties. However, the current determination of structure and process parameters of SPCs are almost entirely based on the experience of researchers, which makes it difficult for people to design high- properties flexible color changing devices according to variable requirements in practical application. Herein, the optimization method on structure and process parameters of SPCs are investigated. Firstly, the influence of lattice structure parameters on the properties of SPCs is studied through numerical calculations, including lattice arrangement modes, lattice constants, as well as shapes and sizes of lattice unit. In addition, the influence of process parameters on the properties of SPCs is studied through experimental tests and analysis, including material types, material ratios, and additives. Eventually, a multi-objective optimization model for structure and process parameters of SPCs is established based on polychromatic sets according to the simulation analysis and experimental test data obtained in this paper, providing a basis for determination of appropriate structure and process parameters for specific application requirements. The model is used to calculate the functional correlation of six typical schemes, and the result showed that ‘scheme 2’ has the highest functional correlation of 15.788, which was the optimal solution. The calculation results are consistent with the experimental results, verifying the feasibility of the model. This study may not only establish an optimization model for structure and process parameters of SPCs but also provides a new way for the selection design of flexible mechanochromic devices.