An exact solution to the electrostatic interaction between an ion-penetrable sphere and an ion-penetrable rod

Lawrence Mark, Jerome L. Kaplan, James Williams

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

No exact solution for the free energy of electrostatic interaction for a charged sphere and rod geometry in an electrolyte solution has yet been proposed. This geometry is interesting because it can be applied to describe macromolecules interacting with a random fiber-matrix for modeling of hindered transport in diffusional systems. Here we present an analytical approach that yields an exact solution to the problem for ion-penetrable - also called 'soft' - sphere and infinitely long rod. This solution is compared to a published finite-element analysis of the same system with nonpenetrable - also called 'hard' - sphere and infinitely long rod maintaining a constant surface charge density restriction. For any ionic strength or ratio of rod radius to sphere radius the ion-penetrable method yields an electrostatic free energy of interaction which is lower than that given by the analysis for hard bodies. This free energy is significantly lower for most parameter value combinations and therefore suggests that one should carefully examine the system being modeled to determine if it is approximated better by a hard body or ion-penetrable body approach. (C) 2000 Academic Press.

Original languageEnglish
Pages (from-to)102-106
Number of pages5
JournalJournal of Colloid and Interface Science
Volume229
Issue number1
DOIs
StatePublished - Sep 1 2000

Fingerprint

Coulomb interactions
rods
Ions
electrostatics
Free energy
free energy
ions
interactions
radii
Geometry
Surface charge
geometry
Ionic strength
Charge density
Macromolecules
macromolecules
Electrolytes
Electrostatics
constrictions
electrolytes

Keywords

  • Double-layer interaction
  • Electrostatic interaction
  • Fiber-matrix
  • Ion-penetrable bodies
  • Poisson-Boltzmann equation

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

An exact solution to the electrostatic interaction between an ion-penetrable sphere and an ion-penetrable rod. / Mark, Lawrence; Kaplan, Jerome L.; Williams, James.

In: Journal of Colloid and Interface Science, Vol. 229, No. 1, 01.09.2000, p. 102-106.

Research output: Contribution to journalArticle

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