methodology was used to study sodium dodecyl sulfate (SDS)

molecules on a graphite surface. Simulations were conducted

at different concentrations of NaCl in water.

Simulations were also conducted at low and high surface surfactant coverage to study aggregation at the water-NaCl/graphite interface.

Results showed that at low surface coverage the SDS molecules form hemicylindrical aggregates in agreement

with AFM experiments. On the other hand, at high surfactant surface coverage, it was observed water layers adsorbed at the solid surface as the concentration of NaCl increased. Therefore, the surfactants tried to form full cylinders.

Hydrogen bond formation between water and surfactant head groups was also studied and it was found that they did not depend on the surfactant concentration. The arrangement of the

NaCl around the polar surfactant head groups were also analyzed in terms of the pair correlation function as a function of its concentration.