EFFECT OF COUNTERIONS ON MICELLAR PROPERTIES OF 2-DODECYLAMINOETHANOL SALTS .2. VISCOSITY AND LIGHT-SCATTERING STUDIES

Viscosity studies of aqueous solutions of the hydrochloride (DHCI), hydrobromide (DHBr), hydriodide (DHI), and nitrate (DHNO3) salts of 2-dodecylaminoethanol revealed that in addition to an initial critical micelle concentration (c.m.c.) a second c.m.c. existed for DHBr, DHI, and DHNO3 at about 5%, 2.5%, and 2.8% w/v concentrations, respectively, but not for DHCl over the concentration range 0-10% w/v. This second c.m.c. was assumed to indicate an increase in size and asymmetry of the micelles. Light-scattering studies showed that the micelle size increased in the order DHCI, DHNO3, DHBr, DHI. Unusual Debye plots obtained for DHI and DHNO3 solutions were related to the changes involved with a second c.m.c. © 1968.