FORMATION AND GROWTH OF BUBBLES IN AQUEOUS SOLUTIONS

Abstract

A preliminary study has been made of the evolution of nitrogen and carbon dioxide from various aqueous solutions subjected, in a simple dilatometer, to decreased pressures. The experiments support the view that all aqueous solutions contain a small number of foci for bubble formation. The presence of these foci is shown by a rapid transient evolution of gas immediately following a large rapid reduction of pressure. The nuclei are rather specific in character: the majority of the particles in suspensions of charcoal, blood corpuscles, and various hydrophobic substances, are unable to function in this manner. When decompression occurs in small steps, evolution of gas is mainly attributable to bubbles formed at preferred spots on the vessel wall, and observed variations in rate of growth have been analysed in terms of the nature of the dissolved gases (nitrogen or Carbon dioxide), the pressure gradient, and the relative importance of pure diffusion and convection under various conditions. In particular, the observed effect of carbon dioxide in accelerating the growth of nitrogen bubbles has been attributed mainly to its high absorption coefficient rather than to any specific effect upon the number of gas nuclei.