Angle-independent colored materials based on the Christiansen effect using phase-separated polymer membranes

Herein, I review the fabrication of new optical composites that exhibit color changes without dyes or pigments covering the whole visible region in response to temperature via changes in both the diffraction properties and the wavelength dispersion of their refractive indices. These systems, which are composed of porous polymer membranes and thermosensitive liquids, display bright coloration caused by the Christiansen effect because the wavelength dispersion of the polymer membranes and the liquids intersect in the visible region. The thermally tunable coloration of the porous polymer membranes containing thermosensitive liquid arises from the coincidence at one wavelength of the dispersion curves of the porous polymer membranes and the thermosensitive liquid portions and depends on the composition and temperature of the thermosensitive liquid.