Stress discoloration detection substrate, preparation method and application

The invention provides a stress discoloration detection substrate, a preparation method and application. The preparation method comprises the following steps: providing a substrate; dispersing the colloidal crystal nano-microspheres in a first low-boiling-point volatile solvent to prepare a colloidal crystal emulsion; the colloidal crystal emulsion is spin-coated on the surface of the substrate, after the first low-boiling-point volatile solvent is removed through drying, the colloidal crystal nano-microspheres are self-assembled and periodically arranged to form colloidal crystals, and the colloidal crystals comprise gaps; diluting a filling material in a second low-boiling-point volatile solvent to prepare a dilute solution; dispensing the dilute solution onto the colloidal crystal, drying to remove the second low-boiling-point volatile solvent, and filling the gap with the filling material to form a colloidal crystal composite structure; wherein in the colloidal crystal composite structure, the volume of t