Complexes between poly(amido amine) dendrimers and poly(methacrlyic acid): insight from molecular dynamics simulations

In this work we present results from fully atomistic molecular dynamics simulations of aqueous solutions of poly(amido amine) dendrimers and poly(methacrylic) acid in the dilute regime and at low ionic strength and physiological pH conditions, in which the polymeric components are charged. We have studied stoichiometric (1:1) and non-stoichiometric (1:2) systems, comprised by dendrimers of two different generations and two different lengths of the linear polyelectrolyte. For all systems studied, a polymer-rich and a solvent-rich region is formed. The polymer-rich region consists of aggregated complexes between the polymeric components bearing similarities to percolated structures met in physical hydrogels. We examine morphological characteristics of the two components as well as the degree of ionic pairing between the different ionic moieties, providing information regarding the degree of physical adsorption of the linear chains on the dendrimer’s surface and that of the respective counterions on the oppositely charged monomers.