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Updated: May 31, 2026

Glass-Based Devices to Generate Drops and Emulsions
Published on: April 5, 2022
How Spontaneous Electrowetting and Surface Charge Affect Drop Motion
Chirag Hinduja1, Benjamin Leibauer1, Rishi Chaurasia1,2
1Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
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 (≤10^{-4}). We find that the drop charge leads to spontaneous electrowetting that decreases the contact angles. 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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