Nanobubbles in water - how to identify them and why they are stable
Licentiate thesis, 2019

Gas bubbles smaller than 1 micrometer in water, commonly referred to as nanobubbles, is a growing field of research and innovation. Applications range from medical imaging and drug delivery to mining industry and environmental remediation. There are many possibilities but important questions remain – how is it possible for small gas bubbles to be stable against dissolution and how can they be detected and differentiated from solid particles and oil droplets ?
In this work we demonstrate that several common nanobubble generation methods can generate contamination particles which can be mistaken for bubbles and that with sufficient cleanliness, neither particles, droplets or bubbles are generated. Theories on nanobubble stability that does not include impurities can thus be dismissed. (Paper 1). Lipid stabilization and the dynamic equilibrium model based on hydrophobic dirt particles appear to be the only valid models for nanobubble stability at present.
We furthermore demonstrate Holographic Nanoparticle Tracking Analysis (H-NTA) as a powerful new method to detect and differentiate between nanobubbles and nanoparticles in the same solution (Paper 2). As H-NTA determines the refractive index of tracked objects, bubbles will differ very significantly from solid particles or oil droplets. The refractive index of a bubble also indicates the amount of adsorbed material as well as possible clustering of multiple bubbles. The method also powerfully enables detection of different particle populationsclose in size and refractive index in a dispersion. The size range is 0.3-0.4 mm to 1.5 mm.

Digital holographic microscopy

Nanoparticle tracking analysis

Dynamic Light scattering


PJ lecture hall
Opponent: Johan Bergenholtz, Göteborgs Universitet


Fredrik Eklund

Chalmers, Physics, Biological Physics

Stable Air Nanobubbles in Water: the Importance of Organic Contaminants

Langmuir,; Vol. 34(2018)p. 11003-11009

Journal article

Subject Categories

Physical Chemistry

Other Chemical Engineering

Other Physics Topics


Chalmers University of Technology

PJ lecture hall

Opponent: Johan Bergenholtz, Göteborgs Universitet

More information

Latest update

3/4/2019 8