The interaction of electrolytes with non-ionic surfactant micelles

MORINI,M., MESSINA,P., SCHULZ,P.

COLLOID AND POLYMER SCIENCE

Springer-Verlag

Lugar: Berlín; Año: 2005 vol. 283 p. 1206 - 1218

0303-402X

The effect of NaCl and HCl on two non-ionic surfactant micelles was studied using several techniques, including conductivity and ion-selective electrodes. Both  surfactants exhibit opposite behavior. When Tween 20 is titrated with HCl  the conductivity notably increases in comparison with water, whereas that of Triton X-100 solutions do not change with respect to water until a certain HCl concentration is reached, when it increases. The hydrogen ion activity is lower in Triton x-100 solutions and higher in Tween 20 solutions than in pure water. Chloride ion activity is higher in Tween 20 solutions tahn in water, whereas in Triton X-100 the activity does not significantly differ from that in water. The activity of sodium ion is lower in Tween 20 solutions than in water, whereas that in triton x-100 does not differ from the tritation of water. These phenomena are explained by the changes in conformation of the non-ionic headgroups, which capturd water, and in some cases ions, modifying the activity of ions in the intermicellar solution.