STUDY OF MICELLAR SOLUTIONS OF ETHOXYLATED DIISONONYLPHENOL BY SMALL-ANGLE NEUTRON-SCATTERING

Micellar solutions of diisononylphenol ethylene oxide in water (D2O/H2 O) were studied by small-angle neutron scattering. It was found that t he micelles are about 45-50 angstrom in size, and do not increase in s ize up to the a surfactant concentration of 5.7 x 10(-2) mol l-1. The micellar shape is close to spherical. The aggregation number of the mi celles is equal to 430. The large value of the observed scattering len gth density may be connected with the hydration of ethylene oxide grou ps. The profile of the scattering length density slowly decreases outw ards from the centre of the micelle. The micellar interaction (studied by the second virial coefficient) changes from attraction to repulsio n as the concentration increases.