Ionic Conductivity Induced Loss of Birefringence of Banana-Shaped Liquid Crystal

Abstract:

The effects of ionic conductivity on the electro-optical properties of a chiral banana-shaped liquid crystal 1,3-phenylene bis{4-[3-chloro-4-(3,7-dimethyloctyloxyl)] phenyliminomethyl} benzoate were investigated with the techniques of polarizing optical microscopy and dielectric spectroscopy. When the banana-shaped liquid crystal was experienced a low-frequency (1 Hz) triangular waveform electric field, its polarizing optical microscopic textures were first turned into gray and then into black at about 95oC, a few degrees lower than the clearing temperature of the banana-shaped liquid crystal. Detailed dielectric spectroscopic characterizations showed that ionic conductivity increased exponentially as the temperature increased from 72 to 110oC. Our results suggested that dominant ionic conductivity near its clearing temperature is responsible for the electric-field induced loss in the birefringence of the banana-shaped liquid crystal.

• Periodical: Key Engineering Materials (Volumes 428-429)
• Pages: 220-223
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.428-429.220
• Online since: January 2010
• Authors: Yuan Ming Huang, Bao Gai Zhai
• Keywords: Banana-Shaped Liquid Crystal, Birefringence, Polarizing Optical Microscopy, Secondary Dynamic Scattering

References

[1] T. Niori, T. Sekine, J. Watanabe et al: J. Mater. Chem., Vol. 6 (1996), p.1231.

[2] C.K. Lee, S.S. Kwon, T.S. Kim et al: Liq. Cryst., Vol. 30, (2003), p.1401.

[3] Y.M. Huang, in: Trends in Optics and Photonics Series: Photorefractive Effects, Materials, and Devices, edited by G. Zhang, D. Kip, D. Nolte, J. Xu, Optical Society of America, Washington (2005).

[4] G.H. Heilmeier and L.A. Zanoni: Appl. Phys. Lett., Vol. 13 (1968), p.91.

[5] Y.M. Huang, L. Chen, F.F. Zhou and B.G. Zhai, in: �ew Trends in Fluid Mechanics Research. edited by F.G. Zhuang, J.C. Li, Tsinghua University Press/Springer, Beijing (2007).

[6] A. Hassner and V. Alexanian: Tetrahedron Lett., Vol. 19 (1978), p.4475.

[7] Y.M. Huang and B.G. Zhai: Mol. Cryst. Liq. Cryst. (in press).