  Recent research has revealed several different techniques for nanoscopic gas
nucleation on submerged surfaces, with findings seemingly in contradiction with
each other. In response to this, we have systematically investigated the
occurrence of surface nanobubbles on a hydrophobised silicon substrate for
various different liquid temperatures and gas concentrations, which we
controlled independently. We found that nanobubbles occupy a distinct region of
this phase space, occurring for gas concentrations of approximately 100-110%.
Below the nanobubble phase we did not detect any gaseous formations on the
substrate, whereas micropancakes (micron wide, nanometer high gaseous domains)
were found at higher temperatures and gas concentrations. We moreover find that
supersaturation of dissolved gases is not a requirement for nucleation of
bubbles.

Fluid Dynamics;Soft Condensed Matter