Nanostructure and dielectric properties of a twist-bend nematic liquid crystal mixture |
| |
| Authors: | RR Ribeiro de Almeida C Zhang O Parri SN Sprunt |
| |
| Institution: | 1. Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA;2. Department of Physics, Maringá State University, Maringá, PR 87020-900, Brazil;3. CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70040-020, Brazil;4. Merck Chemicals Ltd., Chilworth Technical Centre, University Parkway, Southampton, UK;5. Department of Physics, Kent State University, Kent, OH 44242, USA |
| |
| Abstract: | We present freeze-fracture transmission electron microscopy (FF-TEM), dielectric spectroscopy and electro-optic measurements on a dimeric liquid crystal mixture, which previously was proposed to form the twist-bend nematic (Ntb) phase. Our FF-TEM studies provide a direct image of a 10.5 nm periodic structure, consistent with the expected nanoscale, heliconical twist-bend modulation of the molecular orientation. Dielectric measurements in the 100 Hz to 10 MHz range reveal three nearly Debye-type dispersion processes in the nematic and the twist-bend phase. Low frequency 8 V/µm electric fields applied on planar cells cause the optical-scale stripe texture (another characteristic feature of the Ntb phase) to disappear. Higher (>16 V/µm) fields gradually realign the heliconical axis along the electric field; it relaxes back after the field removal. |
| |
| Keywords: | twist-bend nematic dielectric electron microscopy electro-optic |
|
|
