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Influence of polar dopant on internal configuration of azoxybenzene nematic-in-water droplets |
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| Authors: | A. V. Dubtsov S. V. Pasechnik D. V. Shmeliova D. A. Semerenko Aleš Iglič Samo Kralj |
| Affiliation: | 1. Problem Laboratory of Molecular Acoustics, Moscow Technological University, Moscow, Russiaalexanderdubtsov@gmail.com;3. Problem Laboratory of Molecular Acoustics, Moscow Technological University, Moscow, Russia;4. Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia;5. Condensed Matter Physics Department, Jo?ef Stefan Institute, Ljubljana, Slovenia;6. Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia |
| Abstract: | We report the study of optical textures and director configurations within nematic-in-water microdroplets of the liquid-crystalline mixtures based on azoxybenzene and cyanobiphenyl (as a polar dopant). Both pure azoxybenzene and polar dopant materials exhibited bipolar configuration within liquid-crystalline droplets, whereas their mixtures at appropriate concentrations spontaneously formed radial droplets. It was found that increasing of the dopant’s concentration resulted in the forward tangential-homeotropic and reentrant homeotropic-tangential anchoring transitions. We also triggered bipolar-to-radial structural transition by UV irradiation providing trans-cis isomerisation of nematogens. Critical irradiation time needed for radial configuration formation was found to decrease with concentration of polar dopant. Mesoscoping modelling is proposed to explain main experimental results. The presented data are discussed for chemical and biological sensing applications. |
| Keywords: | Liquid crystals azoxybenzene polar dopant microdroplets director configuration UV irradiation trans-cis isomerisation structural transformation |