The entropy of formation of the mercury/methanol interface

Abstract

The entropy of formation of the mercury/methanol interface has been calculated from double layer capacity and interfacial tension measurements. In contrast to results for aqueous and propylene carbonate solutions, the plot of entropy against electrode charge density passes through a minimum at negative charge densities and a maximum at positive charge densities in the same regions where a minimum and maximum are found on the capacity curve. The excess surface entropy of methanol is negative for all charge densities, indicating that the solvent is more structured at the mercury surface than in the bulk. The results have been discussed in terms of the three state model in which the charge dependence of the entropy is attributed to reorientation of solvent dipoles at the interface.