Lee Jun-Yong, Lee Jae Hoon, Lev Bohdan, Kim Jong-Hyun
Department of Physics, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134, Korea.
Bogolyubov Institute for Theoretical Physics of the NAS of Ukraine, Metrolohichna Str.14-b, Kyiv, 03680, Ukraine.
Phys Rev E. 2022 Jul;106(1-1):014706. doi: 10.1103/PhysRevE.106.014706.
The presented study opens a perspective to investigate the effects of local flow on nematic liquid crystals. A particle rotated in nematic fluids typically generates a rotationally symmetric local flow, which causes a change in the director orientation. The director above the threshold velocity has a particular angle determined by the ratio of Leslie coefficients, α_{2}/α_{3}. In 5CB liquid crystals, this director angle with respect to the flow is approximately 13^{∘}. The angle is calculated through Ericksen-Leslie theory. The angle is not dependent on rotation frequency or particle size but temperature. The area of the influenced region increases with the rotation frequency and particle size. The changes in radius of the influenced region are calculated theoretically using Ericksen number. Further, an interference pattern appears at the edge of the influenced region by the refractive indexes mismatch between the influenced region and the rest. We experimentally obtain the thickness of the influenced region analyzing intervals of the pattern.
本研究为探究局部流动向列型液晶的影响开辟了一条途径。在向列型流体中旋转的粒子通常会产生旋转对称的局部流动，这会导致指向矢方向发生变化。高于阈值速度时，指向矢具有由莱斯利系数之比α₂/α₃确定的特定角度。在5CB液晶中，该指向矢相对于流动的角度约为13°。该角度通过埃里克森 - 莱斯利理论计算得出。该角度不依赖于旋转频率或粒子大小，而是取决于温度。受影响区域的面积随旋转频率和粒子大小而增加。利用埃里克森数从理论上计算受影响区域半径的变化。此外，由于受影响区域与其余部分之间的折射率不匹配，在受影响区域的边缘会出现干涉图样。我们通过分析图样的间隔实验获得受影响区域的厚度。
