Electrowetting of Partially Wetting Thin Nanofluid Films

Abstract

It is observed that the presence of negatively charged, suspended nanoparticles significantly changes the electric-field-induced spreading and contact line dynamics of partially wetting liquid films. Image-analyzing interferometry is used to accurately measure the meniscus profile, including the spatial change in the meniscus curvature. The nanoparticle-containing meniscus exhibits enhanced spreading with an increase in the particle size and weight fraction. The instantaneous contact line velocities are measured using video microscopy and a frame-by-frame analysis of the extracted images. The effects of electric field polarity reversal on the flow toward the contact line are explored as well. The movement of the meniscus is analyzed taking into account the capillary forces and Maxwell-stress-induced flows. An analytical model based on the Young-Laplace equation is used to analyze the electric-field-induced contact line motion, and the model-predicted velocities are compared to the experiments.

Magnetowetting of Ferrofluidic Thin Liquid Films

“…It could be inferred from the augmented Young Laplace equation35455060, that the rise in the curvature of the capillary region applies a net capillary suction causing the film to retract. The suction is predominantly felt by the thinner part of the film (first few fringes) wherein, the relative magnitude of the forward acceleration is lower in comparison to those in the vicinity of the capillary region.…”

“…studied the contact line dynamics of thin liquid films and reported the contact line instabilities associated with satellite drop formation, subjected to electrical actuation. Recently, Chakraborty et al 45. investigated the effect of introducing negatively charged nano particles to the thin liquid film (TLF) and studied the associated dynamics by subjecting the thin film to DC electric field.…”

Oscillating nanofluid droplet for micro-cooling

“…The presence of nanoparticles alters the interfacial energy near the TCL [39] and also increases the microscopic curvature close to the TCL [47]. The 'lubricating effect' induced by the presence of nanoparticles augments the structural disjoining pressure [48] near the TCL and helps in increasing the contact line spreading [49].…”

Phenomenological model of wetting charged dielectric surfaces and its testing with plasma-treated polymer films and inflatable balloons

“…Wetting of charged surfaces has attracted the attention of researchers in the last decade [1][2][3][4][5][6].…”

“…Electrical charging of surfaces has an effect on contact angles [1,2,4], dynamics of the triple line [3,6] and other interfacial phenomena. The practical interest in the wetting of charged surfaces is based on the fact that they enable, with no mechanical parts, the control of liquid movement and/or a quick change of states of the system [4].…”