ELECTKOPHORETIC MOBILITIES OF DECYLAMMONIUM CHLORIDE MICELLES
Oct., 1961
1807
THE ELECTROPHORETIC MOBILITIES AND CRITICAL MICEIiLE CONCENTRATIONS OF THE DECYL-, DODECYL- AXD TETRADECYLTRIMETHYLAMMONIUM CHLORIDE MICELLES ANI) THEIR MIXTURES BY HORSTW. HOYEIZ AND h s v z MARMO (:hemistry Department, Hunter College of the City University of New Yo&, New York 21, N . lr, fieceived June 87, 1.960
The electrophoretic mobilities of the decyl-, dodecyl- and tetradecyltrimethylammonium chloride micelles were studied a t 25" as functions of their concentrations in aqueous solution. The values obtained were 2.78, 3.50 and 5.06 X 10P c m 2 per voltrsec., respectively, a t the corresponding critical micelle concentrations. The mobilities of mixtures of the dodecyl and tetradecyl quaternary compounds, but not the corresponding critical micelle concentrations, were found to be linear functions of the mole fractions of the two substances. Addition of dodecyl alcohol to the dodecyltrimethylammonium chloride solution gave values of the mobility essentially that of the pure quaternary amine salt a t its crit,ical micelle concentration. The data require that 74% of the gegenions surround the micelle in a compact double layer while the remaining 26% constitute the diffuse double layer, the potential of which is essentially that given by the zeta potential.
Introduction The present investigation was undertaken to extend our experimental information concerning tmheelectrophoretic mobility of colloidal electrolytes, specifically that of the micelles of the alkyl tximethylanimonium chlorides and their mixtures. Previous work had been concerned with the mobilities of the sodium lauryl sulfate micelles' and that of the micelles of the decyl-, dodecyl- and tetradecylamine hydrochlorides.2 Included with t'he latter was :t study of the effect of temperature on the mobilitfy of the dodecylamine hydrochloride niicelle. 111 the present work we wished to study the mobility of the decyl-, dodecyl- and tetradecyltrimethylammonium chloride micelles and the micelles produced by mixtures of these substances wit>hone anot)her. Included in our study was an
