Structural changes at the interface between polycrystalline Ag and electrolyte solutions containing surfactants as probe molecules

• A combination of structural changes occurs at the polycrystalline Ag electrode/solution interface in the presence of surfactants.
• Due to field-dipole interactions water and adsorbate molecules change their orientation.
• With increasing negative potentials the adsorbed layer undergoes a transition from a dense liquid state to a thinner one.

Structural changes are detected at the interface between polycrystalline Ag electrodes and electrolyte solutions containing surfactants as probe molecules. Capacitance and impedance measurements indicate that in aqueous solutions water and 1-butanol molecules change their position on the electrode due to dipole-field interaction. In methanolic solutions such a change is indicated to occur only for triphenyphosphine oxide molecules. The above changes in both solvents are taking place along with the transition of the adsorbed layer from a dense liquid state to a thinner one with increasing negative potentials.