Xiang Ying, Liu Yi-Kun, Buka Ágnes, Éber Nándor, Zhang Zhi-Yong, Xu Ming-Ya, Wang Everett
School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China.
State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jan;89(1):012502. doi: 10.1103/PhysRevE.89.012502. Epub 2014 Jan 6.
Two kinds of electroconvection patterns in an ether-bridged bent-core nematic liquid crystal material (BCN), which appear in different frequency ranges, are examined and compared. One is a longitudinal pattern with the stripes parallel to the orientation of the BCN and with a periodicity of approximately the cell thickness, occurring in the high-frequency range of several hundreds Hz; the other one is oblique stripes, which results in a zigzag pattern, and appears in the low-frequency range of several tens Hz. In addition, within an intermediate-frequency range, transformations from oblique to longitudinal and then to normal stripes occur at increased ac voltages. In particular, we investigated the temperature behavior of longitudinal and oblique stripes: When the temperature T increases and approaches the clearing temperature Tc, the contrast of the domains is enhanced and the frequency range of existence becomes wider, while the onset voltages increase only moderately instead of diverging, thus suggesting an isotropic mechanism of pattern formation.
