Templating of inorganic nanoparticles by PAMAM/PEG dendrimer-star polymers

Poly(amidoamine) (PAMAM) dendrimers with amine endgroups (PAMAM-NH2) are converted to starlike copolymers by grafting of monofunctional poly(ethylene glycol) (PEG) 'arms' onto the dendrimer endgroups. Generation 4, 7, and 10 dendrimers are converted to 60-arm, 235-arm, and 750-arm PAMAM/PEG stars, respectively. The dendrimer-stars are studied as polymer templates for stabilization of gold and cadmium sulfide nanoparticles of 1-6 nm diameter. PAMAM/PEG star templating reactions are studied by aqueous gel permeation chromatography, ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. PAMAM/PEG stars effectively control nanoparticle size in the same way as PAMAM-NH2 dendrimers. However, PAMAM/PEG stars are miscible with a wider range of solvents and with selected polymers (e.g. polymethyl methacrylate). Potential applications of dendrimer-inorganic hybrid materials (solution-phase catalysis, additives for polymer blends) could benefit from the versatile solubility of PAMAM/PEG stars. (C) 2002 Published by Elsevier Science Ltd.