Archive ouverte HAL – Free energy of cylindrical polyions: Analytical results

Emmanuel Trizac 1 Gabriel Tellez 2

Emmanuel Trizac, Gabriel Tellez. Free energy of cylindrical polyions: Analytical results. Journal of Chemical Physics, American Institute of Physics, 2019, 151 (12), pp.124904. ⟨10.1063/1.5121724⟩. ⟨hal-02395512⟩

Within the Poisson-Boltzmann (PB) framework useful for a wealth of charged soft matter problems, we work out the Coulombic grand potential of a long cylindrical charged polyion in a binary electrolyte solution of arbitrary valency and for low salt concentration. We obtain the exact analytical low-salt asymptotic expression for the grand potential, derived from known properties of the exact solutions to the cylindrical PB equation. These results are relevant for understanding nucleic acid processes. In practice, our expressions are accurate for arbitrary polyion charges, provided their radius is smaller than the Debye length defined by the electrolyte.

  • 1. LPTMS - Laboratoire de Physique Théorique et Modèles Statistiques
  • 2. Departamento de Fisica