论文标题
电网诱导的液滴质质底物的跳跃运动的分析预测:润湿状态的效果
Analytical prediction of electrowetting-induced jumping motion for droplets on textured hydrophobic substrates: Effects of the wetting states
论文作者
论文摘要
用电视施加的电压可以通过更改三相界面张力的内在平衡来诱导单个液滴的高度,滑动甚至跳跃,这在数十年来数十年来已被广泛用于微流体和实验室 - A-A-CHIP设备中的液滴操纵。在本文中,我们介绍了在具有不同润湿状态的质感疏水表面上液滴液滴的跳速的分析预测。特别是,我们考虑在质感疏水底物上进行液滴润湿,并在液滴和底物之间施加电压。一旦关闭电压,电网发行中存储在液滴中的能量,甚至可能导致液滴脱离。系统地讨论了初始和电润湿状态,即卡西 - 巴克斯特状态和温泽尔状态,对液滴的跳速。基于能量守恒,分析了表面能,内部粘性耗散和不同润湿状态下液滴的动能之间的能量转换。系统地得出了预测不同液滴润湿状态的跳速速度的近形公式。最后,获得了具有不同润湿状态的平坦和纹理基板上液滴诱导的液滴诱导的跳速的统一形式,这可以描述各种润湿条件的跳跃运动。这项工作提供了理论上的见解,以准确控制电网诱导的液滴在质感疏水表面上的跳跃运动。
Electric voltage applied in electrowetting can induce speading, sliding and even jumping of an individual droplet by changing the intrinsic balance of three-phase interfacial tensions, which has been widely used for droplet manipulating in microfluidics and lab-on-a-chip devices in over decades. In the present paper, we present an analytical prediction of jumping velocity for droplets electrowetting on textured hydrophobic surfaces with different wetting states. In particular, we consider a liquid droplet wetting on a textured hydrophobic substrate with a voltage applied between the droplet and the substrate. Once the voltage is turned off, the energy stored in the droplet during the electrowetting releases and could even result in the detachment of the droplet. The effects of the initial and electro-wetting states, i.e. Cassie-Baxter state and Wenzel state, on the jumping velocity of droplets are systematically discussed. Based on energy conservation, the energy conversion between the surface energy, internal viscous dissipation and the kinetic energy of droplets in different wetting states are analysed. The close-form formulas to predict the jumping velocity for different droplet wetting states are systematically derived. Finally, the unified form for predicting the electrowetting-induced jumping velocity of droplets on both flat and textured substrates with different wetting states is obtained, which can describe the jumping motion with various wetting conditions. This work provide theoretical insights on accurate control of the electrowetting-induced jumping motion of droplets on textured hydrophobic surfaces.