  The primary attribute of interest of surface nanobubbles is their unusual
stability and a number of theories trying to explain this have been put
forward. Interestingly, the dissolution of nanobubbles is a topic that did not
receive a lot of attention yet. In this work we applied two different
experimental procedures which should cause gaseous nanobubbles to completely
dissolve. In our experiments we nucleated nanobubble-like objects by putting a
drop of water on HOPG using a plastic syringe and disposable needle. In method
A, the nanobubble-like objects were exposed to a flow of degassed water (1.17
mg/l) for 96 hours. In method B, the ambient pressure was lowered in order to
degas the liquid and the nanobubble-like objects. Interestingly, the
nanobubble-like objects remained stable after exposure to both methods. After
thorough investigation of the procedures and materials used during our
experiments, we found that the nanobubble-like object were induced by the use
of disposable needles in which PDMS contaminated the water. It is very
important for the nanobubble community to be aware of the fact that, although
features look and behave like nanobubbles, in some cases they might in fact be
or induced by contamination. The presence of contamination could also resolve
some inconsistencies found in the nanobubble literature.
