EVIDENCE OF IONIC ADSORPTION ON C(12)E(6) NONIONIC MICELLAR SOLUTIONS

In this paper we present conductivity measurements on different concen trations of C(12)E(6) non-ionic surfactant solutions as a function of temperature and buffer ionic strength. The experimental data were anal ysed by means of Looyenga equation. The isothermal slopes of the linea rized Looyenga equation depend on the ionic strength, showing saturati on effect. Our results indicate that one of the basic hypotheses of th e mixture equations is not fulfilled. Adsorption of light ions at mice llar interface is necessary to justify the experimental data. Then for non-ionic surfactant solutions the ion adsorption prevents any explic it computation of the micellar hydrated volume.