Max Dombrowski

2023

1. Herbst, M., Dombrowski, M.O., Preisig, N., Dieterich, S., Giesselmann, F., Mésini, P., Stubenrauch, C.: Gelled lyotropic nematic liquid crystals. Liquid Crystals. 0, 1–11 (2023). https://doi.org/10.1080/02678292.2023.2201583.
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   Abstract

   ABSTRACTLyotropic liquid crystal gels (LLC gels) are versatile materials which combine the anisotropy of a liquid crystal with the mechanical stability of a gel. We succeeded in gelling the rare calamitic nematic NC phase of two different micellar LLC systems with the low molecular weight gelator (LMWG) 3,5-bis-(5-hexylcarbamoyl-pentoxy)-benzoic acid hexyl ester (BHPB-6). The systems of choice are: (1) a binary LLC system with the surfactant N,N-dimethyl-N-ethyl-1-hexadecylammonium bromide (CDEAB) and water; (2) a ternary LLC system with the surfactant N,N,N-trimethyl-N-tetradecylammonium bromide (C14TAB), n-decanol, and water. The obtained gels show optical birefringence and no macroscopic flow. Freeze fracture electron microscopy (FFEM) images show ribbon-like gel fibres that form the gel network and can stack into thicker bundles, while small-angle X-ray scattering (SAXS) confirms the coexistence of the nematic NC phase and the gel network. The growth of the gel network was monitored with time-resolved SAXS measurements. Additionally, significant gel ageing effects were observed in rheology measurements, showing that the gel strengthens with time. With this study, we considerably broaden the pool of available surfactant-based LLC gels and pave a way to macroscopically aligned LLC gels with the goal to apply them as stimuli-responsive actuators and sensors.

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   /brokenurl# https://doi.org/10.1080/02678292.2023.2201583