Color characteristics of mechanochromic photonic bandgap composites

Actively modulating the interparticle lattice constant and/or refractive index contrast of a three-dimensional dielectric structure which exhibits a periodicity comparable to the wavelength of light can result in a variation of the optical diffraction properties. Achieving this modulation with an imposed strain is refereed to as mechanochromism. The color characteristics of opalescent elastomeric films composed of colloidal crystals have been studied at various strain states. These elastomeric photonic bandgap composites exhibit rejection wavelength shifts of over 200 nm and reflected colors that are characterized by color purities ranging from 0.52 to 0.86 and dominant wavelengths ranging from 597 nm to 464 nm.