Structural formation and many-body effect of concentrated dendrimer solutions by computer simulations

Takamichi Terao

doi:10.1107/s0021889807018055

Abstract

Coarse-grained molecular dynamics simulations have been performed in order to study charged dendrimers in an aqueous solution. The structure factor, counterion distribution and effective interaction between molecules are clarified numerically. In particular, the many-body interactions in a triplet system are investigated, which is of importance in concentrated systems. These results shed new light on the analysis of recent small-angle X-ray and neutron scattering experiments on dendrimer solutions.

Highlights

The effective interaction and the phase behavior of soft colloidal systems have become subjects of strong interest
These results indicate that both the overlap of monomers and that of counterions play an important role in determining the effective interaction, which is a specific feature of charged soft colloidal systems in an aqueous solution
Hynninen et al have performed a numerical study of the effect of attractive interaction on the phase behavior of suspensions of charged colloidal particles (Hynninen et al, 2004)

Summary

Introduction

The effective interaction and the phase behavior of soft colloidal systems have become subjects of strong interest. Dendrimers are highly branched, tree-like macromolecules (Ballauf & Likos, 2004; Nisato et al, 2000; Chen et al, 2000) They are nano size with spherical shapes and are representative of soft colloidal particles. Wu et al have investigated three-body interactions among charged colloidal particles and their effect on phase behavior using Monte Carlo simulation (Wu et al, 2000). They found that the three-body force can be repulsive or attractive, depending on macroion-to-macroion separation. It is indicated that most of the counterions exist within each dendrimer molecule

Models

Numerical results

Conclusions