Unique Behavior of Dendritic Macromolecules: Intrinsic Viscosity of Polyether Dendrimers

Poly(3,5-dihydroxybenzyl alc.) dendrimers made by the convergent growth approach are characterized by size exclusion chromatog. (SEC) with coupled mol.-wt.-sensitive detection. SEC chromatograms are as narrow as chromatograms of polystyrene with mol.-wt. distributions .apprxeq. 1.04, and do not broaden appreciably with increasing dendrimer generation, g. Values of wt.-av. mol. wt. obtained from light scattering detection are in agreement with the mol. wts. of the structures anticipated from the synthetic strategy. Intrinsic viscosity, obtained from SEC viscosity detection, passes through a characteristic max. as a function of g, while the refractive index increment appears to pass through a min. Hydrodynamic radii, calcd. from intrinsic viscosity data, increase approx. linearly with dendrimer generation. The data are in agreement with recent simulations of Lescanec and Muthukumar that predict a max. in intrinsic viscosity as a function of g. This suggests, but does not directly prove, that the d. of these dendrimers decreases monotonically from the center.

Duke Scholars

Author Michael Rubinstein Thomas Lord Department of Mechanical Engineering and Materia ...