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

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.