Koibuchi Hiroshi
Department of Industrial Engineering, National Institute of Technology, Ibaraki College, Nakane 866, Hitachinaka, Ibaraki 312-8508, Japan.
Polymers (Basel). 2018 Jul 9;10(7):757. doi: 10.3390/polym10070757.
In this paper, we show that the 3D Finsler geometry (FG) modeling technique successfully explains a reported experimental result: a thin liquid crystal elastomer (LCE) disk floating on the water surface deforms under light irradiation. In the reported experiment, the upper surface is illuminated by a light spot, and the nematic ordering of directors is influenced, but the nematic ordering remains unchanged on the lower surface contacting the water. This inhomogeneity of the director orientation on/inside the LCE is considered as the origin of the shape change that drives the disk on the water in the direction opposite the movement of the light spot. However, the mechanism of the shape change is still insufficiently understood because to date, the positional variable for the polymer has not been directly included in the interaction energy of the models for this system. We find that this shape change of the disk can be reproduced using the FG model. In this FG model, the interaction between σ, which represents the director field corresponding to the directional degrees of LC, and the polymer position is introduced via the Finsler metric. This interaction, which is a direct consequence of the geometry deformation, provides a good description of the shape deformation of the LCE disk under light irradiation.
在本文中，我们表明三维芬斯勒几何（FG）建模技术成功解释了一个已报道的实验结果：漂浮在水面上的薄液晶弹性体（LCE）圆盘在光照下会变形。在已报道的实验中，上表面被一个光斑照亮，指向矢的向列有序性受到影响，但与水接触的下表面的向列有序性保持不变。LCE上/内部指向矢取向的这种不均匀性被认为是形状变化的起源，这种形状变化驱使圆盘在水面上朝着与光斑移动方向相反的方向运动。然而，形状变化的机制仍未得到充分理解，因为迄今为止，聚合物的位置变量尚未直接纳入该系统模型的相互作用能中。我们发现，使用FG模型可以重现圆盘的这种形状变化。在这个FG模型中，通过芬斯勒度量引入了代表与液晶方向度相对应的指向矢场的σ与聚合物位置之间的相互作用。这种相互作用是几何变形的直接结果，很好地描述了光照下LCE圆盘的形状变形。
