Gaining Control through Frustration: Two-Fold Approach for Liquid Crystal Three-Dimensional Command Layers

Abstract

The alignment of Liquid Crystal (LC) molecules, essential for their applications in optical devices such as displays, is usually controlled by functionalizing their confining surfaces by either patterning or by specific surfactants that induce either parallel or perpendicular molecular arrangement. Inducing a bistable alignment, such as in the new zenithal bistable displays, offers new opportunities in terms of new functionalities and lower energy consumption but a full understanding of such bistable alignment appears still complicated. Here we present a simple phenomenological model that includes surface topography and chemistry. The predicted orientational transitions and bistable states are in excellent agreement with experiments, thus making this a proper tool to design multistable 3D command layers.

Fully Stable and Homogeneous Lyotropic Liquid Crystal Alignment on Anisotropic Surfaces

“…As long as the molecular length of the self‐assembled surfactant structures on the surface does not exceed the characteristic depths of the grooves too much, it is able to effectively couple the anisotropic structural topography of the PI to the LCLC stacks at the interface. Optimization of both the width and depth of the grooves in the surface structure has been reported for thermotropic liquid crystals and LCLCs, although for the latter, this work suggests that the presence of a surfactant plays a crucial role.…”

Phase transition and dewetting of a 5CB liquid crystal thin film on a topographically patterned substrate

“…Particularly for the LC molecules that deposit inside a substrate groove, adjacent locations of the base and the side walls of the groove impose different direction of the director of the molecules, resulting in much higher numbers of inversion lines or defects. 44 As a consequence of that the spin coated as-cast lm on patterned substrates entrap large amount of energy at room temperature. During the phase transition, when such a lm is heated to the isotropic state, these trapped excess energy within the disclination points and inversion lines get released and the molecules reorganize themselves.…”

“…within liquid crystal cells, which offer novel in display technologies such as enhanced viewing angle, zenithal bistable displays at reduce power consumption. 43,44 However, phase transition and dewetting of an LC thin lm on a topographically patterned substrates has never been explored before.…”

Electric field generation of Skyrmion-like structures in a nematic liquid crystal

“…Such an approach already proved useful for functionalization of surfaces interacting with NLC for switching optimization and orientation control. 18 , 21 …”