Young and Young-Laplace equations for a static ridge of nematic liquid crystal, and transitions between equilibrium states

• Main Authors: Cousins, J.R.L (Author), Duffy, B.R (Author), Mottram, N.J (Author), Wilson, S.K (Author)
• Format: Article
• Language: English
• Published: Royal Society Publishing 2022
• Subjects: Contact angle; Continuous transitions; dewetting; De-wetting; Discontinuous transition; Equilibrium state; Integrodifferential equations; Laplace equation; Laplace transforms; nematic liquid crystals; Nematic liquid crystals; Nematics; Partial wetting; Phase interfaces; Solid substrates; wetting; Wetting; Young equation; Young Laplace equation; Young-Laplace equation; Young's equation; Young's-Laplace equation
• Online Access: View Fulltext in Publisher

 Motivated by the need for greater understanding of systems that involve interfaces between a nematic liquid crystal, a solid substrate and a passive gas that include nematic-substrate-gas three-phase contact lines, we analyse a two-dimensional static ridge of nematic resting on a solid substrate in an atmosphere of passive gas. Specifically, we obtain the first complete theoretical description for this system, including nematic Young and Young-Laplace equations, and then, making the assumption that anchoring breaking occurs in regions adjacent to the contact lines, we use the nematic Young equations to determine the continuous and discontinuous transitions that occur between the equilibrium states of complete wetting, partial wetting and complete dewetting. In particular, in addition to continuous transitions analogous to those that occur in the classical case of an isotropic liquid, we find a variety of discontinuous transitions, as well as contact-angle hysteresis, and regions of parameter space in which there exist multiple partial wetting states that do not occur in the classical case. © 2022 The Authors.