KINETICS OF CONDENSATION ON SOLUBLE NUCLEI

A kinetic equation is derived to describe the fluctuational overcoming of an activation barrier by drops nucleated in a supersaturated vapor on condensation nuclei that are soluble in the drops. It is shown that the activation energy in the case of heterogeneous condensation is the gradient of the heights of the potential hill and potential well of the work of drop formation, rather than the height of the potential hill of the work for the critical drop (as in the case of homogeneous condensation). It is found that the rate of heterogeneous formation of supercritical drops is steady. The subsequent growth of these drops is unconstrained. An incubation period is established for the steady-state growth. It is shown that the incubation period also determines the characteristic time scale for the development of the heterogeneous phase transformation throughout the metastable region of the vapor, where the degree of supersaturation is low. Estimates are made of characteristics of the process of condensation on soluble nuclei in the case when the substance of the nuclei is surface-inactive.