A Small-Angle Neutron Scattering Study of Micelles Formed in Aqueous Mixtures of a Nonionic Alkylglucoside and an Anionic Surfactant

Abstract

The size and shape of micelles formed in aqueous mixtures of the anionic surfactant sodium dodcyl sulfate (SDS) and the nonionic sugar based surfactant n-decyl b -D–glucopyranoside (C10G) at different concentrations of added salt have been investigated with small-angle neutron and static light scattering. Rather small prolate ellipsoidal micelles form in the absence of added salt and in [NaCl] = 10 mM in D2O that grow considerably in length to large rods as the electrolyte concentration is raised to [NaCl] = 0.1 M. In excess of nonionic surfactant ([SDS]:[C10G] = 1:3) in [NaCl] = 0.1 M in D2O several thousands of Angstrom long worm-like micelles are observed. Most interestingly, a large isotope solvent effect was observed from static light scattering data according to which the micelles formed at [SDS]:[C10G] = 1:3 and [NaCl] = 0.1 M in H2O are at least five times smaller than micelles formed in the corresponding samples in D2O.