Understanding the unusual behaviour of nanobubbles

Nano-bubble dispersions are a novel type of nanoscale bubble system. The most peculiar characteristic of these nano-bubbles is their apparent extraordinary longevity, being able to last for weeks and months. Existing theories, however, predict that they should dissolve extremely quickly. Thus, to fully exploit their potential benefits, major developments are needed in the science underpinning their existence and behaviour. The overall aim of this project is to study both experimentally and theoretically the underlying mechanisms by which these nano-bubble dispersions come to exist and persist, and explain some of their unusual properties. The aim would be to unravel the effects on pre-formed nano-bubble suspensions and on nano-bubble formation, size distribution, coalescence, stability and dynamic behaviour, of a number factors including: liquid phase properties: type of liquid, surfactants, ionic strength and pH; gas phase properties including type of gas and gas concentration; processing conditions such as shear and temperature under steady and transient modes; and, consequently, gain insight into the apparent immunity of bulk nano-bubbles to Ostwald ripening. The work includes collaboration with Queen's University Belfast, Daresbury Laboratory as well as the Medical School at Birmingham. We would like to link a PhD project to this EPSRC programme which would be looking at some of these phenomena but also investigate some of the revolutionary applications of bulk nanobubbles such as drug delivery, flavour retention and surface cleaning.