Improved simulation method for the calculation of the intrinsic viscosity of some dendrimer molecules

TL;DR

This paper introduces an improved simulation method for calculating the intrinsic viscosity of dendrimers, incorporating correction factors, realistic angle distributions, and molecular dynamics data to better match experimental results.

Contribution

The new method enhances previous models by including bead volume corrections, internal angle distributions, and molecular dynamics-based distances for more accurate dendrimer viscosity predictions.

Findings

Accurately describes experimental data for polypropylene-imide dendrimers in water.

Requires all three modifications for polybenzylether dendrimers in THF.

Improves agreement between simulations and experimental measurements.

Abstract

A method previously proposed for calculating the radius of gyration and the intrinsic viscosity of dendrimers is modified to give a more accurate description of existing experimental data. The new method includes some features that were not previously considered, namely: a) a correction term to take into account the contribution of individual friction beads, whose volumes are not negligible in comparison with the molecule size, b) a realistic distribution of internal angles between successive beads that define branching points in the molecule, c) a distribution of distances between branching points computed from Molecular Dynamics simulations of a small dendrimer with explicit solvent. Modification a) alone is able to give a good description of the experimental results obtained for polypropylene-imide with a diaminobutane core in water, while the simultaneous use of the three modifications is needed to adequately describe the experimental data of monodendrons and tridendrons of polybenzylether in THF.