Morphologies of planar polyelectrolyte brushes in a poor solvent: molecular dynamics simulations and scaling analysis

Jan-Michael Y Carrillo; Andrey V Dobrynin

doi:10.1021/la901839j

Morphologies of planar polyelectrolyte brushes in a poor solvent: molecular dynamics simulations and scaling analysis

Langmuir. 2009 Nov 17;25(22):13158-68. doi: 10.1021/la901839j.

Authors

Jan-Michael Y Carrillo¹, Andrey V Dobrynin

Affiliation

¹ Polymer Program, Institute of Materials Science and Department of Physics, University of Connecticut, 2152 Hillside Road, U-3046, Storrs, Connecticut 06269, USA.

PMID: 19899820
DOI: 10.1021/la901839j

Abstract

Using molecular dynamics simulations and scaling analysis, we study the effect of the solvent quality for the polymer backbone, the strength of the electrostatic interactions, the chain degree of polymerization, and the brush grafting density on conformations of the planar polyelectrolyte brushes in salt-free solutions. Polyelectrolyte brush forms: (1) vertically oriented cylindrical aggregates (bundles of chains), (2) maze-like aggregate structures, or (3) thin polymeric layer covering a substrate. These different brush morphologies appear as a result of the fine interplay between electrostatic and short-range monomer-monomer interactions. The brush thickness shows nonmonotonic dependence on the value of the Bjerrum length. It first increases with the increasing value of the Bjerrum length, and then it begins to decrease. This behavior is a result of counterion condensation within a brush volume.