MICELLAR PROPERTIES OF OCTYLGLUCOSIDE IN AQUEOUS-SOLUTIONS

Micellar properties of a nonionic surfactant, octylglucoside, in water and their change with temperature in the range between 5 and 58°C were studied with intensity and quasi-elastic light scattering, and sedimentation velocity and equilibrium methods. The molar mass and hydrodynamic radius of the micelle formed at 22°C were determined to be 25000 g mole-1 (an aggregation number of 87) and 2.35 nm, respectively. The shape of the micelle was presumed from its hydrodynamic properties to be an oblate or prolate ellipsoid not much different from a sphere and with significant amount of hydration. The apparent micellization enthalpy estimated from the temperature dependence of critical micelle concentration was positive in the temperature range studied, while it decreased steeply above 25°C. Molar mass of the micelle varied with temperature, having a maximum value, 36000 g mole-1, at 36°C. The second virial coefficient estimated from the Debye plot increased monotonously with temperature, from a negative value to a positive one, becoming zero at 39°C. These results were compared with those of other kinds of surfactants to reveal the characteristics of solution properties of octylglucoside. © 1990.