Skip to main content »

Trinity College Dublin

Existence of Micrometer-Scale Water Droplets at Solvent/Air Interfaces

Langmuir  28, 13218-13223 (2012)

The ability to control the stability of droplets at fluid interfaces is central to many applications, including mineral and particulate separation techniques and emulsion based technologies such as paints.  While much is known about macroscopic droplets the behaviour of micron and nanoscale droplets are less well understood.  In particular, standard surface tension values for pure liquids predict that water droplets are unstable at the liquid/air interfaces of many common organic solvents.

Using a novel optical technique we demonstrated the existence of  micron size water droplets at these interfaces and provided estimates of their stability.   We showed that droplets were stabilized by the presence of a nanoscale solvent layer that reduced the surface energy of the exposed droplet at the solvent/air interface.