Molecular dynamics simulations were performed for a series of AB 2 dendrimer models, in explicit-solvent solutions where the ratio R g /L ͑R g is the radius of gyration and L the size of the simulation box͒ is kept between 0.15рR g /Lр0.2. Results on static properties ͑size, shape, density profiles͒ are in good agreement with recent theoretical and experimental studies. Dynamic properties are systematically investigated on the local and entire molecule length scale. The dynamic characteristics of the examined models capture the qualitative behavior observed experimentally in dendrimer molecules. The systematic and comparative nature of this study affords detailed insight into the origin and the relative contribution of different relaxational mechanisms in the observed dynamic spectra.

No abstract

Brownian dynamics simulations of perfect dendrimers up to the sixth generation have been performed under the influence of simple shear flow. Hydrodynamic and excluded volume interactions have been taken into account explicitly. The onset of shear-thinning is observed to occur at lower shear rates for larger dendrimers (i.e. more generations). As the generation increases, the zero shear rate intrinsic viscosity reaches a maximum and begins to fall. The radius of gyration, the hydrodynamic radius, the translational mobility, and radial density profiles including the location of the terminal groups are also reported.

No abstract

No abstract