jp8b07619_si_003.avi (3.42 MB)
Electrocoalescence of Two Drops with Different Surfactant Concentrations Suspended in Oil
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posted on 2018-09-18, 00:00 authored by Xiaoming Luo, Haoran Yin, Haipeng Yan, Xin Huang, Donghai Yang, Limin HeIn
this study, the electrocoalescence characteristic of two drops
with different surfactant concentrations suspended in oil is revealed.
Different from the symmetrical coalescence of identical drops, the
asymmetrical liquid bridge is induced by the capillary force, which
involves the interfacial tension gradient between the drops. In addition,
a mushroom-like jet is formed during asymmetrical coalescence, causing
mixing of drops. A characteristic time considering the interfacial
tension gradient is proposed to describe the asymmetrical liquid bridge
evolution. The mushroom-like jet is found to be driven by the pressure
difference between drops, which has a positive correlation with the
interfacial tension gradient. Moreover, it is found that the electrocoalescence
time is shortened as the interfacial tension increases. This study
indicates that increasing the interfacial tension gradient will enhance
the jet flow rate and reduce the coalescence time, which is of significance
to improve the mixing efficiency of the drops.