Intrinsic viscosity of dendrimers via equilibrium molecular dynamics

Abstract

Equilibrium molecular dynamics have been used to simulate systems of trifunctional dendrimers in an explicit Lennard-Jones solvent. Solution and solvent viscosities, calculated using the Green–Kubo relation, have been used for the first time to determine the intrinsic viscosity of dendrimers of generations three to seven inclusive. Results reveal a peak in the intrinsic viscosity against generation at generation five, which is in good agreement with experiment and with previous computational efforts using stochastic simulation techniques. A second method employing a variation of the Green–Kubo formula is used to yield intrinsic viscosities directly. This method produces results in quantitative agreement with the traditional Green–Kubo approach. In contrast to the findings above, Flory–Fox intrinsic viscosity estimates using the simulated gyration radii reveal an intrinsic viscosity that steadily decreases from values at early generations.