Thermal Switching of the Reflection in Chiral Nematic\nMesoporous Organosilica Films Infiltrated with Liquid Crystals

Abstract

Materials\nthat undergo stimulus-induced optical changes are important for many\nnew technologies. In this paper, we describe a new free-standing silica-based\ncomposite film that exhibits reversible thermochromic reflection,\ninduced by a liquid crystalline guest in the pores of iridescent mesoporous\nfilms. We demonstrate that selective reflection from the novel mesoporous\norganosilica material with chiral nematic organization can be reversibly\nswitched by thermal cycling of the 8CB guest between its isotropic\nand liquid crystalline states, which was proven by solid-state NMR\nexperiments. The switching of the optical properties of the chiral\nsolid-state host by stimulus-induced transitions of the guest opens\nthe possibility of applications for these novel materials in sensors\nand displays.