Flexoelectric fluid membrane vesicles in spherical confinement

¹ Department of Physics, Faculty of Arts and Sciences, Eastern Mediterranean University Famagusta, North Cyprus via Mersin 10, Turkey
² Laboratoire de Physique des Matériaux, Université des Sciences et de la Technologie Houari Boumediene BP 32 El-Alia Bab-Ezzouar, 16111 Alger, Algeria
³ Laboratoire de Physique et Chimie Théoriques - UMR 7019, Université de Lorraine 1 boulevard Arago, 57070 Metz, France

Received: 3 June 2020
Accepted: 26 June 2020

Abstract

The morphology of spherically confined flexoelectric fluid membrane vesicles in an external uniform electric field is studied numerically. Due to the deformations induced by the confinement, the membrane becomes polarized resulting in an interaction with the external field. The equilibrium shapes of the vesicle without electric field can be classified in a geometrical phase diagram as a function of scaled area and reduced volume (Kahraman O. et al., EPL, 97 (2012) 68008; Kahraman O. et al., New. J. Phys., 14 (2012) 095021). When the area of the membrane is only slightly larger than the area of the confining sphere, a single axisymmetric invagination appears. A non-vanishing electric field induces an additional elongation of the confined vesicle which is either perpendicular or parallel depending on the sign of the electric field parameter. Higher values of the surface area or the electric field parameter can reduce the symmetry of the system leading to more complex folding. We present the resulting shapes and show that transition lines are shifted in the presence of an electric field. The obtained folding patterns could be of interest for biophysical and technological applications alike.