In-situ measurements of twist and bend elastic constants in oblique helicoidal cholesteric
arXiv:2205.00909 · doi:10.1103/PhysRevE.106.024702
Abstract
Unique electro-optical properties of the oblique helicoidal cholesteric (ChOH) stem from its heliconical director structure. An applied electric field preserves the single harmonic modulation of the director while tuning the ChOH period and the corresponding Bragg peak wavelength within a broad spectral range. We use the response of ChOH to the electric field to measure the elastic constants of twist K22 and bend K33 directly in the cholesteric phase. The temperature dependencies of K22 and K33 allow us to determine the range of the electric tunability of the ChOH pitch and the heliconical angle. The data are important for understanding how molecular composition and chirality influence macroscopic elastic properties of the chiral liquid crystals and for the development of ChOH-based optical devices.
arXiv comment19 pages, 10 figures
References in corpus (9)
- Nematic twist-bend phase with nanoscale modulation of molecular orientation
- A Twist-Bend Chiral Helix of 8nm Pitch in a Nematic Liquid Crystal of Achiral Molecular Dimers
- Electrically tunable selective reflection of light from ultraviolet to visible and infrared by heliconical cholesterics
- Electrooptic response of chiral nematic with oblique helicoidal director
- Elastic and viscous properties of nematic dimer CB7CB
- Comparative analysis of anisotropic material properties of uniaxial nematics formed by flexible dimers and rod-like monomers
- Nanosecond electro-optics of nematic liquid crystal with negative dielectric anisotropy
- Tuning selective reflection of light by surface anchoring in cholesteric cells with oblique helicoidal structures
- Twist-bend nematics and heliconical cholesterics: a physico-chemical analysis of phase transitions and related specific properties