Antiferroelectric phase in liquid crystalline compounds containing an azo group in their molecular core |
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| Authors: | Miroslav Ka?par Věra Hamplová Natalia Podoliak Dorothee Nonnenmacher Frank Giesselmann |
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| Institution: | 1. Institute of Physics, Academy of Sciences of the Czech Republic , Prague, Czech Republic;2. Institute of Physical Chemistry, University of Stuttgart , Stuttgart, Germany |
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| Abstract: | Novel lactic acid derivatives containing an azo group in their molecular core have been synthesised and their mesomorphic properties established. Compounds with a short aliphatic non-chiral chain exhibited the SmA* phase and ferroelectric (FE) SmC* phase. The monotropic antiferroelectric (AF) phase was found in the homologues with a longer terminal chain. Spontaneous polarisation and tilt angle were measured for the FE and AF phases. Dielectric spectroscopy in the frequency range 1 Hz–10 MHz was carried out and dielectric properties established within the temperature range of the smectic phases. Two high frequency modes were detected in the AF phase. Small-angle X-ray measurements were conducted, and the temperature dependence of layer spacing values is established and discussed. |
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| Keywords: | antiferroelectric liquid crystals ferroelectricity dielectric properties lactate group photosensitivity azo linkage |
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