Free energy pathways of a Multistable Liquid Crystal Device

Kusumaatmaja, H.; Majumdar, A.

Abstract

The planar bistable device [Tsakonas et al., Appl. Phys. Lett., 2007, 90, 111913] is known to have two distinct classes of stable equilibria: the diagonal and rotated solutions. We model this device within the two-dimensional Landau-de Gennes theory, with a surface potential and without any external fields. We systematically compute a special class of transition pathways, referred to as minimum energy pathways, between the stable equilibria that provide new information about how the equilibria are connected in the Landau-de Gennes free energy landscape. These transition pathways exhibit an intermediate transition state, which is a saddle point of the Landau-de Gennes free energy. We numerically compute the structural details of the transition states, the optimal transition pathways and the free energy barriers between the equilibria, as a function of the surface anchoring strength. For strong anchoring, the transition pathways are mediated by defects whereas we get defect-free transition pathways for moderate and weak anchoring. In the weak anchoring limit, we recover a cusp catastrophe situation for which the rotated state acts as a transition state connecting two different diagonal states.

Citation

Kusumaatmaja, H., & Majumdar, A. (2015). Free energy pathways of a Multistable Liquid Crystal Device. Soft Matter, 11(24), 4809-4817. https://doi.org/10.1039/c5sm00578g

• Journal Article Type: Article
• Acceptance Date: May 11, 2015
• Publication Date: Jun 28, 2015
• Deposit Date: May 16, 2015
• Publicly Available Date: May 27, 2015
• Journal: Soft Matter
• Print ISSN: 1744-683X
• Electronic ISSN: 1744-6848
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 24
• Pages: 4809-4817
• DOI: https://doi.org/10.1039/c5sm00578g
• Related Public URLs: http://arxiv.org/abs/1503.05514