FisMat2017 - Submission - View

Abstract's title: Switching dynamics in cholesteric liquid crystal emulsions
Submitting author: Federico Fadda
Affiliation: Dipartimento di Fisica, Università di Bari
Affiliation Address: Dipartimento di Fisica, Università di Bari, and INFN, Sezione di Bari, Via Amendola 173, 70126 Bari, Italy
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Giuseppe Gonnella Dipartimento di Fisica and Sezione INFN Università di Bari Via Amendola 173 70126 Bari, Davide Marenduzzo SUPA School of Physics and Astronomy University of Edinburgh EH9 3JZ UK, Enzo Orlandini Dipartimento di Fisica and Sezione INFN Università di Padova 35131 Padova
Abstract

In this work, using a hybrid Lattice Boltzmann algorithm, we numerically study the switching dynamics of a 2D cholesteric emulsion droplet immersed in an isotropic fluid under an electric field, which is either uniform or rotating. The overall dynamics depend strongly on the magnitude and on the direction (with respect to the cholesteric axis) of the applied field, on the anchoring of the director at the droplet surface and on the elasticity. If the surface anchoring is homeotropic and a uniform field is parallel to the cholesteric axis, the director undergoes deep elastic deformations and the droplet typically gets stuck into metastable states which are rich in topological defects. When the surface anchoring is tangential, the effects due to the electric field are overall less dramatic, as a small number of topological defects form at equilibrium. The application of a field perpendicular to the cholesteric axis usually has negligible effects on the defect dynamics. The presence of a rotating electric field of varying frequency fosters the rotation of the droplet. In the past isotropic droplets in nematic solvent, liquid crystal blue phases under electric field and equilibrium defect structures in cholesteric droplets had been investigated. Our results represent a first step to understand the dynamical response of a cholesteric droplet under an electric field and its possible application in designing novel liquid-crystal based devices.