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Dataset associated with 'Dielectric properties of liquid crystalline dimer mixtures exhibiting the nematic and twist-bend nematic phases'

Trbojevic, Nina and Read, Daniel and Nagaraj, Mamatha (2017) Dataset associated with 'Dielectric properties of liquid crystalline dimer mixtures exhibiting the nematic and twist-bend nematic phases'. University of Leeds. [Dataset] https://doi.org/10.5518/203

Dataset description

A detailed investigation of the thermal and dielectric properties of a series of binary mixtures exhibiting the nematic (N) and twist-bend nematic (NTB) liquid crystal phases is presented. The mixtures consist of an achiral, dimeric liquid crystal CB7CB, which forms the nematic and twist-bend nematic phases, and a calamitic liquid crystal 5CB, which shows the nematic phase. As the concentration of the calamitic liquid crystal is increased, the transition temperatures decrease linearly, and the width of the nematic phase increases. The enthalpies of phase transitions obtained from DSC measurements show that on increasing the concentration of 5CB in the binary mixtures, the enthalpy associated with the N to NTB phase transitions reduces considerably compared to a clear first order N-NTB transition in pure CB7CB. The real and imaginary parts of the dielectric permittivity are measured as a function of frequency from 100 Hz to 2 MHz in the nematic and twist-bend nematic phases in planar and homeotropic devices. A significant decrease in the average dielectric permittivity as a function of temperature for mixtures forming the NTB phase is observed. Measurements of the imaginary part of the dielectric permittivity show a relaxation peak in the measured frequency window for all of the mixtures exhibiting the NTB phase. The activation energy associated with this relaxation process is calculated and is shown to remain constant irrespective of the composition of the mixtures.

Keywords:	twist-bend nematic, dimeric liquid crystals, phase diagram, dielectric spectroscopy
Divisions:	Faculty of Engineering and Physical Sciences > School of Physics and Astronomy
Related resources:	Location Type https://doi.org/10.1103/PhysRevE.96.052703 Publication http://eprints.whiterose.ac.uk/123381/
License:	Creative Commons Attribution 4.0 International (CC BY 4.0)
Date deposited:	03 Nov 2017 14:56
URI:	http://archive.researchdata.leeds.ac.uk/id/eprint/274
Additional details Additional details Creators: Creators ORCID Other ID Email Primary affiliation Primary affiliation ID Primary affiliation ID type Secondary affiliation Secondary affiliation ID Secondary affiliation ID type Trbojevic, Nina https://orcid.org/0000-0001-7385-2579 Read, Daniel https://orcid.org/0000-0003-1194-9273 Nagaraj, Mamatha https://orcid.org/0000-0001-9713-1362 Type of data: Dataset Publication date: 2017 Resource language: English Publisher: University of Leeds Contact Email Address: pynt@leeds.ac.uk Last Modified: 15 Nov 2017 09:57

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