ИСТИНА

Liquid crystalline dispersions attract much attention because of a wide spectrum of their applications in electro-optics, photonics and chemical sensing. In our study, we have investigated the light-induced structural transitions (Fig. 1) in the droplets of nematic liquid crystal (NLC) doped with (0.08%) carbosilane dendrimer of the fifth generation with azobenzene terminal groups. The spherical droplets in the bulk of glycerol and the droplets laid down on the glass cell substrate were considered. The droplet structure transformations induced by the light diode (LD) irradiation were investigated. At  = 400 nm, the bipolar structure of all droplets in the bulk of glycerol changes to radial one, while each droplet on the glass substrate initially having one point defect becomes defectless with almost homeotropic director orientation. This effect is accociated with the adsorbtion of dendrimer molecules on the interface between NLC and glycerol and with trans→cis isomer conversion of azobenzene fragments under near-UV illumination. The initial droplet structures can be restored by cis→trans isomerisation due to thermal relaxation or LD illumination at  = 467 nm. This study was supported by the joint project of the Russian Science Foundation (project no. 16-43-03010) and Ministry of Science and Technology of Taiwan (contract no. MOST 105-2923-E-006-007).