SOLVATION AND COUNTERION-DISTRIBUTION OF SODIUM OCTANOATE MICELLES STUDIED BY MOLECULAR-DYNAMICS SIMULATIONS

In this publication we have studied molecular details of the solvent l ayer and the counterion distribution around sodium octanoate micelles. The results were obtained from computer experiments using molecular d ynamics simulations. From the model it was possible to calculate the r adial distribution functions, which give informations on the average d istance 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. The se results coincide well with experimental data and with other types o f computer experiments. In analogy to water molecules it was also poss ible to get informations on the distribution of sodium counterions aro und the charged micelle. These results are in general agreement with e xperimental and theoretical data and they can be used to calculate Cou lomb interactions and the net surface charge of the micellar aggregate s.