I will discuss large-scale molecular dynamics simulations of the electrowetting behavior of molecular fluids in graphenic nanoscale confinements (10-70 nm). It will be shown that the static contact angles of water, aqueous electrolytes and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF<sub>4</sub>]) exhibit unexpected, asymmetric dependencies on electric field polarity. The solid-liquid interfacial tensions, which, according to the Young-Lippmann equation are expected to drive these dependencies, have been calculated independently by integrating the reversible work performed upon introducing positive and negative surface charges. Paradoxically, the interfacial tensions show either no dependence on the polarity of the electric field, or show a dependence, which is exactly opposite to the one anticipated based on the observed contact angles. To explain these observations, I will discuss fluid structural effects in the three-phase contact line, whose properties are expected to contribute to nanoscale wettability.

Asymmetric electrowetting at the nanoscale: Molecular dynamics simulations of molecular fluids on graphene

253rd National Meeting (2017)

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