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Photomanipulation of the Mechanical Properties in a Liquid Crystal with Azo‐Containing Bent‐Core Mesogens
Author(s) -
Kurachkina Marharyta,
Nádasi Hajnalka,
Alaasar Mohamed,
Tschierske Carsten,
Eremin Alexey
Publication year - 2020
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.202000125
Subject(s) - liquid crystal , azobenzene , materials science , photoisomerization , phase (matter) , crystallography , phase transition , optics , chemical physics , condensed matter physics , composite material , organic chemistry , chemistry , optoelectronics , physics , polymer , catalysis , isomerization
We demonstrate the reversible photomanipulation of the bulk mechanical properties in the azobenzene‐containing bent‐core liquid crystal. The azobenzene groups in the mesogens exhibit reversible cis‐trans photoisomerization abilities. An unprecedentedly large reduction by the factor of more than 5 of the splay elastic constant in a cybotactic‐type nematic phase was found under exposure to the UV. This opens up the possibility to manipulate the mechanical properties of liquid crystals using light. The liquid crystal material is also distinguished by the sign inversion of low‐frequency temperature‐dependent dielectric anisotropy. Such behavior can be related to the presence of smectic‐like nanoclusters both in the isotropic phase near the clearing point and in the cybotactic nematic phase.