A molecular dynamics investigation of structure and dynamics of SDS and SDBS micelles

Abstract

Sodium dodecylbenzene sulfonate (SDSB) is a major constituent of some synthetic detergents with billions of kilograms produced and dispersed in the environment annually. It has now reached a prominent role in the emerging field of nanotechnology for possible uses in exfoliating graphitic materials. It differs from the highly computationally investigated sodium dodecyl sulfate (SDS) because of the presence of a phenyl group attached to the anionic head. In this paper, using MD simulations, we characterize computationally for the first time SDBS micelles. SDBS and SDS micelles in explicit water show that the SDBS micelle is more spherical with a ratio of eccentricities, e_SDBS/e_SDS, equal to 0.117/0.154. The mean micellar radius is similar for the two surfactants and equal to 19.4 Å for SDS and 20.0 Å for SDBS. Analysis of the solvent accessible surface area, chain direction, end-to-end distances, and carbon–carbon bond conformations shows that the hydrophobic core made by the dodecyl chains of SDBS is more tightly packed than SDS.