The effect of dendrimer charge inversion in complexes with linear polyelectrolytes

The structure of complexes formed by charged dendrimers and oppositely charged linear chains with a charge of at least the same as that of dendrimers was studied by computer simulation using the Brownian dynamics method. The freely jointed, free-draining model of the dendrimer and the linear chain was used. Elec-trostatic interactions were considered in terms of the Debye–Hückel approximation with a Debye radius that exceeds the dendrimer size. It was shown that the number of chain monomeric units adsorbed on the dendrimer is greater than necessary for its neutralization; i.e., the effect of charge inversion is observed. A nonmonotonic function relating the amount of monomer units of the chain to its length was derived and agrees qualitatively with the theoretical prediction by Nguyen and Shklovskii for a complex of a linear chain with an oppositely charged spherical macroion. This nonmonotonic relationship was also revealed during study of the mean-square radius of gyration, the monomer-density radial distribution function, and the mass and charge distribution inside the complex.