Effects of Quenched Disorder on Liquid Crystal: A Simulation of Rough Cylinder Confinement

摘要

Quenched disorder (QD) and surface field are two key factors in nano-confinement researches. Despite decades of development, distinguishing the two factors is still challenging. To explore this issue, liquid crystals (LCs) confined in both smooth and rough cylinders are simulated and compared with the bulk LCs. The rough cylinders are aperiodical and produced firstly via randomly spherical indentation. Results show that QD reduces the order of orientation and translation, lessens the anisotropy of diffusion and shortens the rotational correlation time of the confined LCs with respect to the surface field. The intensity of the QD effects depends on the magnitude of the roughness of cylinders. In addition, the anisotropic diffusion of LCs exhibits a circular pattern when LCs system are cooled from the isotropic phase to the smectic phase. The simulated anisotropic diffusion validates the affine transformation model for the Bulk system in the isotropic and nematic phases. The model, however, underestimates the anisotropy of the confined systems. These results are helpful to develop physical models and explain experimental phenomena for confinement researches.