Solvation and Counterion-Distribution of Sodium Octanoate Micelles Studied by Molecular Dynamics Simulations

Abstract

In this publication we have studied molecular details of the solvent layer and the counterion distribution around sodium octanoate micelles. The results were obtained from computer experiments using molecular dynamics simulations. From the model it was possible to calculate the radial distribution functions, which give informations on the average distance between water molecules and the polar surfactant head groups. We observed different types of solvent layers. From these experiments it was also possible to calculate the number of hydrogen bonds between surrounding water molecules and the polar surfactant head groups. These results coincide well with experimental data and with other types of computer experiments. In analogy to water molecules it was also possible to get informations on the distribution of sodium counterions around the charged micelle. These results are in general agreement with experimental and theoretical data and they can be used to calculate Coulomb interactions and the net surface charge of the micellar aggregates.