Pre-Gibbs Adsorption by Surface Rearrangement

Abstract

IT has been an unresolved paradox¹ that for many solutions such as soap the surface tension is only a fraction of that of water, and yet the Gibbs theorem strictly requires that in the neighbourhood of the surface there should be proportionately more water than in the bulk of the solution. When the solution is thoroughly mixed and uniform right up to the surface (dynamic surface tension), the surface tension is practically the same as that of water. After a few thousandths of a second, the surface tension is very greatly lowered, in spite of the accumulation of more water in the surface demanded by Gibbs.