2003/05/29 by Ikuo S. Sogami, Sogami, Ikuo S.
Engineering · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Condensed Matter (cond-mat) #Elasticity and Material Modeling #FOS: Physical sciences #Thermoelastic and Magnetoelastic Phenomena #cond-mat
paper · pdf · doi:10.48550/arxiv.cond-mat/0305674
4 pages, revtex4
arxiv created 2003/05/29 · openalex publication_date 2003/05/29 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A generating functional which results in the Poisson-Boltzmann equation and boundary conditions for an average electric potential of a macroionic suspension through an extremal condition is constructed in a mean field theory. The extremum of the generating functional turns out to be identical with the Helmholtz free energy of the system which has an integral representation in terms of the average electric potential satisfying the Poisson-Boltzmann equation. From the Helmholtz free energy, the chemical potentials of small ions and \it chemical potentials of effective valencies of macroions are calculated and, as the total sum of them, an integral representation of the Gibbs free energy of the system is derived. Difference of two free energies leads to an equation of state for osmotic pressure of small ion gas in an environment of macroions in the suspension.