Flexible mechanochromic photonic crystals: routes to visual sensors and their mechanical properties
The past decade has witnessed remarkable advances in mechanochromic photonic crystals with potential applications in smart displays, strain sensors, biomedical devices, household products, fingerprint identification, and civil engineering. This review summarizes recent developments in flexible mechanochromic photonic crystals, including the inspiration of materials from nature, principles for fabrication, characterization of mechanical properties, and applications in smart strain-colour sensing. Flexible mechanochromic photonic crystals have further enhanced and broadened the applications of mechanochromic photonic crystals. In addition to conformal deformation, they can enable or enhance structural colour effects without additional energy consumption, especially for monitoring mechanical deformation, failure and fracture in bulk materials to prevent hazardous incidents.