Ratschow Aaron D, Butt Hans-Jürgen, Hardt Steffen, Weber Stefan A L
Institute for Nano- and Microfluidics, TU Darmstadt, Peter-Grünberg-Str. 10, 64289 Darmstadt, Germany.
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Soft Matter. 2025 Feb 12;21(7):1251-1262. doi: 10.1039/d4sm01289e.
This review is about drops of a liquid with high dielectric permittivity that slide over a solid surface with high electrical resistivity. A typical situation is a water drop sliding down a tilted hydrophobic plate. It has been realized recently that such drops spontaneously acquire a charge. The opposite charge is deposited behind the drop as a surface charge. Generated electric potentials in the drops can easily reach 1 kV and more. This phenomenon has been termed slide or contact electrification. It is the soft matter analog to triboelectrification, which occurs in solid friction. Slide electrification turned out to be ubiquitous in everyday life and technical applications. It will change our common knowledge of dynamic wetting. Studying slide electrification is complex because the outcome of a wetting experiment depends on the history. For this reason, a series of drops, rather than single drops, are analyzed to gain quantitative understanding. Here, we review the fundamental understanding of slide electrification and its limits. We describe consequences, on drop motion and advancing and receding contact angles and we address open questions.
本综述围绕具有高介电常数的液体滴在高电阻率固体表面滑动展开。一个典型的情形是水滴在倾斜的疏水板上滑落。最近人们发现，此类液滴会自发带电。相反电荷会作为表面电荷沉积在液滴后方。液滴中产生的电势很容易达到1千伏甚至更高。这一现象被称为滑动或接触起电。它是固体摩擦中发生的摩擦起电在软物质领域的类似现象。事实证明，滑动起电在日常生活和技术应用中无处不在。它将改变我们对动态润湿的常识认知。研究滑动起电很复杂，因为润湿实验的结果取决于其过程。因此，为了获得定量认识，我们分析的是一系列液滴，而非单个液滴。在此，我们综述对滑动起电的基本认识及其局限性。我们描述其对液滴运动、前进和后退接触角的影响，并探讨一些悬而未决的问题。
