Complexation of a Linear Polyelectrolyte with a Charged Dendrimer: Polyelectrolyte Stiffness Effects
WD Tian and YQ Na, MACROMOLECULES, 43, 1575-1582 (2010).
We employ extensive coarse-grained molecular dynamics simulations to explore the influence of rigidity of linear polyelectrolyte (PE) on the dendrimer-PE complexes. We find that the size of PE chain increases and its shape changes from oblate to prolate concomitant with the interesting conformation transformations from "coil"-like to "U"-like or "V"-like and further to "rod"-like as the stiffness of PE is increased. We also find that, as a soft nanoparticle, the changes of the size and the shape of charged dendrimer depend not only on the stiffness of PE but also on Bjerrum length of system. This can be explained in terms of two competing interaction energies: the bending energy and the electrostatic attractive energy. Furthermore, we witness that the effective charge of dendrimer exists a jump at both Bjerrum lengths studied, but the overcharge only appears at the large Bjerrum length. Moreover, we propose that there may exist an optimum stiffness of bioactive guest in the complexes for delivery and release.
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