Homogeneous nucleation of bubbles in solutions at pressures above the vapor pressure of the pure liquid

The homogeneous nucleation of bubbles in liquid-gas solutions is considered theoretically and experimentally. The stability of a homogenous liquid phase is shown to be specified by the critical radius, Rc. If Rc is negative or infinite, then the liquid is stable; however, if Rc is positive then the liquid is metastable. The prediction of the pressure at which nucleation occurs follows from nucleation theory. At a given temperature, the presence of a dissolved gas is shown to significantly raise the pressure at which nucleation occurs. These predictions were experimentally tested for ethyl ether droplets containing dissolved nitrogen using an isothermal decompression technique. Results are presented for a range of gas concentrations including values for which it is predicted that nucleation should occur at pressures greater than the vapor pressure of the pure liquid. Good agreement between theoretical and measured nucleation pressures was obtained.