Molecular models for Sodium Dodecyl Sulphate in aqueous solution to reduce the micelle time formation in molecular simulation

Abstract

In this work two Sodium Dodecyl Sulphate (SDS) molecular models are proposed; one based on the Explicit-Atom (EA) approach while the other on the United-Atom (UA) approach. A SDS aqueous solution was simulated using the TIP4P/ε potential for water. With the EA model the micellar aggregate spent less than 1 ns of simulation time to be formed. This is a quite low simulation time compared to the 23 ns spent by existing SDS models to attain the same micellar formation. When both proposed models are compared, micellar formation from EA model is 10 times faster than the UA model. The time reduction is due to the implementation of two repulsive sites in the carbon atoms on the hydrophobic tails. To validate the models, density, radial distribution functions, radius of gyration and shear viscosity were calculated; results were in good agreement with those reported in literature.