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arXiv · 2602.03362

How Spontaneous Electrowetting and Surface Charge affect Drop Motion

Chirag Hinduja·Benjamin Leibauer·Rishi Chaurasia·Nikolaus Knorr·Aaron D. Ratschow·Shalini Singh·Hans-Jürgen Butt·Rüdiger Berger
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Abstract

Water drops sliding on hydrophobic surfaces spontaneously separate charges at their rear. It is unclear how this charge separation affects the contact angles of a sliding drop. We slide grounded and insulated drops on hydrophobic surfaces at low capillary numbers (\leq 10^{-4}). We find that drop charge leads to spontaneous electrowetting, which decreases the contact angles. Additionally, the deposited charges lead to a surface charge effect and decrease the contact angle. Both phenomena compensate each other at the receding contact line, resulting in an insignificant change in the receding contact angle of a sliding drop.

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Chirag Hinduja, Benjamin Leibauer, Rishi Chaurasia, Nikolaus Knorr, Aaron D. Ratschow, Shalini Singh, Hans-Jürgen Butt, Rüdiger Berger. 2026-02-03. How Spontaneous Electrowetting and Surface Charge affect Drop Motion. https://doi.org/10.1103/9mzt-v9cl

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