Combining high-speed photography with electric current measurement, weinvestigate the electrocoalescence of Pickering emulsion droplets. Under highenough electric field, the originally-stable droplets coalesce via two distinctapproaches: normal coalescence and abnormal coalescence. In the normalcoalescence, a liquid bridge grows continuously and merges two dropletstogether, similar to the classical picture. In the abnormal coalescence,however, the bridge fails to grow indefinitely; instead it breaks upspontaneously due to the geometric constraint from particle shells. Suchconnecting-then-breaking cycles repeat multiple times, until a stableconnection is established. In depth analysis indicates that the defect size inparticle shells determines the exact merging behaviors: when the defect size islarger than a critical size around the particle diameter, normal coalescencewill show up; while abnormal coalescence will appear for coatings with smallerdefects.
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