Electric-Field-Induced Instabilities in Thin Liquid Trilayers Confined between Patterned Electrodes

Abstract

Electric-field-induced instabilities of trilayer of immiscible thin films confined between both planar and patterned electrodes have been explored by the linear stability analysis (LSA) and the long-wave nonlinear simulations. The twin liquid–liquid interfaces of a trilayer can undergo either in-phase bending or antiphase squeezing or mixed modes of evolution. The linear and nonlinear analyses together uncover the conditions under which these modes evolve and subsequently form an array of interesting, complex patterns. The study confirms that when the middle layer is of the highest or lowest dielectric permittivity than the other layers the interfaces undergo a squeezing mode of deformation. In other cases, the interfaces evolve in the bending mode, except for the situations where the linear growth coefficient versus wavenumber curves in the LSA show a bimodal behavior and the interfaces evolve in a mixed mode. The LSA also highlights the importance of the ratios of the thermodynamic parameters such as th...