Thermally induced mass transfer between nanobubbles and micropancakes

Abstract

The response of nanoscopic gas phases at solid-liquid interfaces to temperature changes remains unclear. We investigated the interactions between surface nanobubbles and underlying micropancakes upon heating. By atomic force microscopy imaging of the same area before and after heating, we found that the surface nanobubbles exhibited various behaviors upon heating: nucleation, growth, and disappearance. The differences in behavior are attributable to the existence of underlying gas phases, such as micropancakes and adsorbed layers. The nucleation sites of the nanobubbles depend on the positions of the micropancakes. The size of the underlying micropancakes is central to the manner of gas transport between the micropancakes and overlying nanobubbles. We propose that the strongly adsorbed gas layers attract dissolved gas molecules and thereby lead to irreversible growth before and after heating.