Hidden photooptically recorded image on polymer dispersed liquid crystal composite #liquidcrystal

Photochromic cholesteric liquid crystal mixture based on cholesterol derivatives doped on chiral photosensitive substance capable of photoisomerization. Liquid crystal mixture was dispersed in polyvinyl alcohol plasticized with glycerol and composite film was irradiated by UV light 365 nm through the mask. Changing in helical twisting power of dopant leads to helix twisting and shift of selective light reflection peak from near IR to visible range. Recorded image becomes visible under application of mechanical deformation on the composite. Pressing of the film results in deformation of the cholesteric droplets and increase of intensity of selectively reflected light.
Material was prepared and studied by my colleague Dr. Nikolai Balenko.
#liquidcrystal #materialscience #physics #chemistry