Nonionic surface-active compounds. V. Effect of electrolyte

Abstract

The effect of electrolyte on the micellar properties in aqueous solution of a series of polyoxyethylene derivatives of lauryl and tridecyl alcohols, and of nonyl phenol, has been studied. Changes in the critical micelle concentration and micellar size have been followed as a function of concentration of various electrolytes. The critical micelle concentration (c.m.c.) is lowered in a way comparable with that observed with ionic surface-active agents, but there is little increase in micellar size, except with the least soluble compounds. With more soluble compounds, in fact, there appears to be a slight decrease in micellar size. Many of the data can be explained in terms of a positive double layer charge arising from hydronium ion formation.