A History of Nanobubbles

TLDR

The paper traces the history of nanobubbles, from early experiments to recent work, discussing how Laplace pressure renders them thermodynamically unstable and how stability is instead governed by dissolution rates, distinguishing bulk from surface nanobubbles. The authors review early evidence, production and characterization methods, gaseous nature, and stability theories for each nanobubble class. They also examine applications of both surface and bulk nanobubbles.

Abstract

We follow the history of nanobubbles from the earliest experiments pointing to their existence to recent years. We cover the effect of Laplace pressure on the thermodynamic stability of nanobubbles and why this implies that nanobubbles are thermodynamically never stable. Therefore, understanding bubble stability becomes a consideration of the rate of bubble dissolution, so the dominant approach to understanding this is discussed. Bulk nanobubbles (or fine bubbles) are treated separately from surface nanobubbles as this reflects their separate histories. For each class of nanobubbles, we look at the early evidence for their existence, methods for the production and characterization of nanobubbles, evidence that they are indeed gaseous, or otherwise, and theories for their stability. We also look at applications of both surface and bulk nanobubbles.