Statics and dynamics of electrowetting on pillar-arrayed surfaces at the nanoscale

Abstract

The statics and dynamics of electrowetting on pillar-arrayed surfaces at the nanoscale are studied using molecular dynamics simulations. Under a gradually increased electric field, a droplet is pushed by the electromechanical force to spread, and goes through the Cassie state, the Cassie-to-Wenzel wetting transition and the Wenzel state, which can be characterized by the electrowetting number at the microscale η m . The expansion of the liquid is direction-dependent and influenced by the surface topology. A positive voltage is induced in the bulk droplet, while a negative one is induced in the liquid confined among the pillars, which makes the liquid hard to spread and further polarize. Based on the molecular kinetic theory and the wetting states, theoretical models have been proposed to comprehend the physical mechanisms in the statics and dynamics of electrowetting, and are validated by our simulations. Our findings may help to understand the electrowetting on microtextured surfaces and assist the future design of engineered surfaces in practical applications.

The Impact of the Electric Field on Surface Condensation of Water Vapor: Insight from Molecular Dynamics Simulation

“…They have found that both the electric field direction and strength could affect the viscosity of water. The wetting properties of water droplets on a surface can also be manipulated by the electric field due to the characteristics of water, including droplet spreading [39], droplet morphology transformation [40,41,42], and contact angle variation [43,44]. The potential application of an electric field on phase changes has also been studied.…”

Wetting and electrowetting on corrugated substrates

“…Nowadays, wetting and EW on special surfaces draw great interest. The general rough surfaces, [23][24][25] curve surfaces, 26,27 and ordered rough surfaces [28][29][30][31] are all paid significant attention. EW, as a prolongation of wetting, has a close relationship with wetting.…”

Computational simulations of pressure-driven nanofluidic behavior

“…, TIP4P, TIP5P以及TIP6P等 [55][56][57][58][59][60][61][62] ), 因此研究水在 刚性CNT的流控行为已经成为当前纳米流控行为研 究中采用的最基本模型 [2,21,39,55,58,[63][64][65][66][67][68][69][70][71][72] . 浸润, Yuan和Zhao研究组 [38,46,[73][74][75] 否仍然有效还存在很多争论 [76][77][78][79][80][81][82][83] . Tolman长度(δ) [84] 通 常被用来描述液滴表面张力(γR, 具有有限曲率半径R) 与液体平面表面张力(γ¥, 曲率半径R为无穷大) [83,[85][86][87] 之间的差别:…”