Electrostatic interactions between Janus particles

Joost de Graaf, Niels Boon, Marjolein Dijkstra, Rene van Roij

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper we study the electrostatic properties of "Janus" spheres with unequal charge densities on both hemispheres. We introduce a method to compare primitive-model Monte Carlo simulations of the ionic double layer with predictions of (mean-field) nonlinear Poisson-Boltzmann theory. We also derive practical Derjaguin Landau Verwey Overbeek (DLVO)-like expressions that describe the Janus-particle pair interactions by mean-field theory. Using a large set of parameters, we are able to probe the range of validity of the Poisson-Boltzmann approximation, and thus of DLVO-like theories, for such particles. For homogeneously charged spheres this range corresponds well to the range that was predicted by field-theoretical studies of homogeneously charged flat surfaces. Moreover, we find similar ranges for colloids with a Janus-type charge distribution. The techniques and parameters we introduce show promise for future studies of an even wider class of charged-patterned particles. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751482]

Original languageEnglish
Article number104910
Number of pages12
JournalThe Journal of Chemical Physics
Volume137
Issue number10
DOIs
Publication statusPublished - 14 Sep 2012

Keywords

  • RESTRICTED-PRIMITIVE-MODEL
  • MONTE-CARLO SIMULATIONS
  • ELECTRIC DOUBLE-LAYERS
  • COLLOIDAL PARTICLES
  • CHARGED-PARTICLES
  • PHASE-BEHAVIOR
  • SOFT MATTER
  • EWALD SUMS
  • ELECTROLYTE
  • ANISOTROPY

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