Structure and Dimensions of PAMAM/PEG Dendrimer-Star Polymers

Published

March 1, 2003

Author(s)

R C. Hedden, Barry J. Bauer

Abstract

Dendrimer-star polymers are prepared by grafting monofunctional poly(ethylene glycol) (PEG) chains of low polydispersity onto the terminal groups of poly(amidoamine) (PAMAM) dendrimers. A novel gel permeation chromatography technique is used to calculate the average number of PEG branches (arms) per star. The maximum number of PEG arms (of Mn = 5,000 g mol-1) ranges from about 30 arms for a Generation 3 dendrimer-star to about 750 arms for a Generation 10 dendrimer-star. Radii of gyration of the stars are measured in dilute solution in a good solvent (methanol-d4) by small-angle neutron scattering (SANS). The stars have measured radii of gyration of (5 to 14) nm. Dendrimer-stars are modeled as a shell of linear chains tethered to a spherical core. The core radius is taken to be the measured hydrodynamic radius of the dendrimer. The density distribution within the shell and the shell thickness are adopted from a model of Vagberg, Cogan, and Gast.The radii of gyration computed from the core-shell model are consistent with the measured values from SANS.

Citation

Macromolecules

Volume

36

Issue

No. 6

Pub Type

Journals

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Keywords

dendrimer, neutron scattering radius of gyration, polymer brush, star polymer

Citation

Hedden, R. and Bauer, B. (2003), Structure and Dimensions of PAMAM/PEG Dendrimer-Star Polymers, Macromolecules, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852070 (Accessed October 30, 2025)