| Abstract |
A controversial discussion regarding the estimation of surface thickness in aqueous ethanol as calculated by Phan and co-workers (2019) from neutron reflectivity experiments and by Bagheri et al. (2016) and Santos and Reis (2018) from surface tension data and equality of chemical potentials is addressed. The theoretical link among equilibrium mole fractions, Gibbs excess concentration, surface molar volume and interfacial thickness developed by Phan and co-workers is rearranged into an explicit expression for the calculation of thickness, which is shown to be inconsistent with their Gibbs excess concentration estimating equation from neutron reflectivity experiments. A correction is proposed, and the recalculated equivalent thickness values present an increase, with increasing ethanol contents, in fair agreement with the values reported by Santos and Reis (2018). (C) 2019 Elsevier B.V. All rights reserved. |
