Order Reconstruction in a Nanoconfined Nematic Liquid Crystal between Two Coaxial Cylinders

Abstract

The dynamics of a disclination loop (s = ±1/2) in nematic liquid crystals constrained between two coaxial cylinders were investigated based on two-dimensional Landau–de Gennes tensorial formalism by using a finite-difference iterative method. The effect of thickness (d = R2 − R1, where R1 and R2 represent the internal and external radii of the cylindrical cavity, respectively) on the director distribution of the defect was simulated using different R1 values. The results show that the order reconstruction occurs at a critical value of dc, which decreases with increasing inner ratio R1. The loop also shrinks, and the defect center deviates from the middle of the system, which is a non-planar structure. The deviation decreases with decreasing d or increasing R1, implying that the system tends to be a planar cell. Two models were then established to analyze the combined effect of non-planar geometry and electric field. The common action of these parameters facilitates order reconstruction, whereas their opposite action complicates the process.

Fine structures of defect cores induced by elastic anisotropy and biaxiality in hybrid alignment nematics

“…We adopt the two-dimensional finite-difference method developed in our previous studies to obtain the numerical simulation results. [23][24][25] Here, the system is relaxed from an initial boundary condition given in Subsection 2.2, and the initial conditions of the left half and right half in the bulk are consistent with the boundary conditions at the left wall and right wall given above. The initial perturbation of twist angle is given as follows: from z = −d/2 to z = d/2, the twist angle changes as…”