Comment on “Simple thermodynamic derivation of the electrocapillary equations” by L. Makkonen [Surf. Sci. 635 (2015) 61-63]

- “Simple thermodynamic derivation of the electrocapillary equations” contains mathematical errors.
- We propose a simplest derivation of the electrocapillary equation using the Gibbs-Duhem relation.
- The both Gokhstein's equations are only artificially distorted forms of the Lippmann equation.
- Therefore, attempts to evaluate validity of the Gokhstein equations are senseless.
- The Lippmann equation does not require checks of its validity as it has been shown earlier.