Frequency-controlled dielectrophoresis-driven wetting of nematic liquid crystals

Brown, C. V., Bhadwal, A. S., Edwards, A. M. J., Sage, I. C., Saxena, A. and Mottram, N. J. (2022) Frequency-controlled dielectrophoresis-driven wetting of nematic liquid crystals. Journal of Physics D: Applied Physics, 55(28), 285302. (doi: 10.1088/1361-6463/ac6466)

Abstract

We show that surface-localized dielectrophoresis-driven wetting of anisotropic nematic liquid crystal sessile droplets obeys the same relationship, cos⁡[θ(V_o)]=cos⁡[θ_Y ]-βV_o^2, which has previously been found for isotropic liquid droplets, even though the nematic liquid crystal phase possesses a uniaxial dielectric permittivity tensor. We also demonstrate that the dielectrowetting coefficient β, which determines the magnitude of the reduction in the contact angle, from θ_Y to θ(V_o ), through the action of a potential difference V_o, can be controlled by the frequency of the applied voltage between interdigitated electrodes beneath a droplet of highly dispersive nematic liquid crystal. Our Q-tensor modelling of the electric field-induced 2-dimensional n-director distortions within a nematic droplet elucidates how this linear relationship holds for voltages when |θ(V_o )-θ_Y | exceeds 3-4 degrees.

• Item Type: Articles
• Additional Information: A. Saxena and A.S. Bhadwal were funded by Merck Chemicals Ltd. and by Nottingham Trent University Ph.D. Scholarships. C.V. Brown, A.M.J. Edwards and N.J. Mottram were funded by the UK EPSRC (Grants EP/J009865/1, EP/R042276/1, and EP/J009873/1, respectively).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Mottram, Professor Nigel

Creator Roles

Mottram, N. J.: Conceptualization, Methodology, Software, Formal analysis, Investigation, Resources, Writing – review and editing, Supervision, Project administration, Funding acquisition

• Authors: Brown, C. V., Bhadwal, A. S., Edwards, A. M. J., Sage, I. C., Saxena, A., and Mottram, N. J.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Journal of Physics D: Applied Physics
• Publisher: IOP Publishing
• ISSN: 0022-3727
• ISSN (Online): 1361-6463
• Published Online: 05 April 2022
• Copyright Holders: Copyright © 2022 The Author(s).
• First Published: First published in Journal of Physics D: Applied Physics 55(28): 285302
• Publisher Policy: Reproduced under a Creative Commons Licence