Molecular Dynamics Simulations of the Protonated G4 PAMAM Dendrimer in an Ionic Liquid System

Molecular dynamics simulations have been carried out for the ionic liquid system constituted by totally protonated PAMAM-EDA cations and Tf2N(-) anions. The conformational characteristics of the PMAM dendrimer (particularly the density profile around the dendrimer center) are compared with those obtained for the same dendrimer in water. We also investigate other features, such as the location of anions relative to the dendrimer molecules, and the interpenetration of the dendrimer cations in the ionic liquid system. It is shown that a substantial amount of anions are present in the outer part of the dendrimer, screening repulsive contacts between different cation molecules and favoring ionic conductivity. Dendrimer cations in the ionic liquid exhibit a significant degree of overlap.