Kinetics of bubble formation and the tensile strength of liquids

A recently developed new approach to the determination of the work of critical cluster formation in the description of nucleation processes is applied here to the description of the kinetics of bubble formation in liquids. This method is a generalization of the classical Gibbs' approach, retaining its advantages and avoiding its shortcomings. For illustration purposes, the method is developed here for the case of bubble formation in a one-component system described by van der Waals' equation of state. The surface tension between liquid and gas is described by a modification of Macleods equation. However, any other relationships specifying the state of the system under consideration, which may be considered eventually as more appropriate, can be employed as well. The method can be extended also straightforwardly to the description of bubble formation in multicomponent liquids. It is shown that the newly developed approach secures, at least, the qualitatively correct description of the behavior of the system not only for small but also for high supersaturations. In particular, similarly to the van der Waals-Cahn and Hilliard and other more advanced density functional calculations in the determination of the work of critical cluster formation, for initial states, approaching the spinodal curve, the work of critical cluster formation is shown to tend to zero. In application of the method to the interpretation of experimental results, the problem of the limits of the tensile strength of liquids is revisited. It is shown that, by applying the newly developed method, the gap between theoretical predictions and experimental observations can be reduced considerably if not totally. This result can be considered as a strong indication of the power of the newly developed method in the interpretation of experimental results on bubble formation, in general. (C) 2002 Elsevier Science B.V. All rights reserved.