Photo-driven effects in twist-bend nematic phases: Dynamic and memory response of liquid crystalline dimers
نویسندگان
چکیده
• Synthesis of new liquid crystal dimers with cyanobiphenyl and azobenzene fragments. The show conventional nematic twist-bend phases. undergo isothermal reversible phase transitions by light irradiation. Re-entrant isotropic phases are formed at sufficiently high dosages. Reversibility the changes can be controlled temperature intensity. We apply UV to control stability phases, N TB , N, in three crystalline nonsymmetric containing light-responsive fragments connected a hexyloxy spacer. dynamic static (5 kHz) dielectric responses (E)-4′-(6-(4-((4-(ethoxy)phenyl)diazenyl)phenoxy)hexyl)-[1,1′-biphenyl]-4-carbonitrile, CB6OAzO2, (E)-4′-(6-(4-((4-(hexyloxy)phenyl)diazenyl)phenoxy)hexyl)-[1,1′-biphenyl]-4-carbonitrile, CB6OAzO6, (E)-4′-(6-(4-((4-hexylphenyl)diazenyl)phenoxy)hexyl)-[1,1′-biphenyl]-4-carbonitrile, CB6OAz6, measured different temperatures, planar homeotropic alignments, application bias alternating electrical fields. CB6OAz(O) n values mean, ε ¯ anisotropy, Δ due dipole moment associated groups. absence ether linkage terminal chain CB6OAz6 reduces - transition increases bend elastic constant, K 3 compared those seen for CB6OAzO6. Isothermal promoted light-irradiation, via trans -to- cis photoisomerisation units, resulting disruption order appearance re-entrant low temperatures. It is possible dynamics reversibility these varying chemical structure dimers, dosage. This may exploited devices using multiple external stimuli.
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ژورنال
عنوان ژورنال: Journal of Molecular Liquids
سال: 2021
ISSN: ['0167-7322', '1873-3166']
DOI: https://doi.org/10.1016/j.molliq.2021.117680