向列液晶在力场作用下扭曲变形特性的研究

Study on the Properties of the Twist Distortion of Nematic Liquid Crystals in the Action of the Force Fields

通过测试向列液晶在不同的预倾角,初始角以及在不同力场作用下偏振光强度的变化,确定液晶分子发生扭曲变形的特性参数:扭曲角、变形的旋转时间和弛豫时间。测试结果表明:在相同力场作用下,液晶在取向层的预倾角愈大,液晶分子的扭曲变形程度也愈大;向列液晶在不同力场作用下产生形变的旋转时间和弛豫时间受液晶弹性常数和粘滞系数的影响,形变的旋转时间小于其弛豫时间;此外,向列液晶在取向层的初始角会影响液晶在力场作用下发生扭曲变形的程度,不同的力场强度下存在一对应于最大扭曲变形的初始角。

By measuring changes of the intensity of the polarized light of nematics at different pretih angles and initiative angles and in different force fields, the characteristic parameters of the twist distortion such as the twist angles, the rotation time and the relaxation time are determined. The results show that the larger is the pretih angle of nematic on the orientational layer in the action of the same force field, the more is the degree of the twist distortion. The rotation time and the relaxation time of distortion in the action of different force fields are affected by the elastic constants and viscosity of nematics, the rotation time is smaller than the relaxation time. Furthermore, the initiative angles of nematics on the orientational layer will affect the degree of the twist distortion in the action of force fields, each intensity of force field is corresponding to the initiative angle which can produce the largest twist distortion.