Simulations of Neutral and Charged Dendrimers in Solvents of Varying Quality

Abstract

We study neutral and charged dendrimers of various generations G, spacer length S, and molecular weight N under systematic variation of the solvent quality ranging from athermal to poor solvents. We use Monte Carlo simulations based on the bond fluctuation model and we take into account explicitly counterions, the full Coulomb and excluded volume interactions. The effect of solvent is accounted for implicitly by a short-range attraction between the monomers. The range of attraction is chosen in order to avoid unphysical freezing effects at temperatures well below the Θ-point. Our simulations support the Flory-type scaling prediction of the dendrimers’ size under all solvent conditions for neutral dendrimers. Neutral dendrimers also display universal scaling properties with respect to the spacer length and spacer self-density. The maximum of electrostatically driven swelling, controlled by osmotically active residual counterions, is found to be nearly independent of solvent quality. Under poor solvent cond...