Solution structure of metal particles prepared in unimolecular reactors of amphiphilic hyperbranched macromolecules

The structure of metal nanoparticles templated by amphiphilic hyperbranched polyethyl-enimine-amides in apolar organic solution was studied by means of small-angle neutron scattering (SANS). SANS measurements at different concentrations revealed that the neat polymer is present as nonaggregated unimolecular micelles for a polymer with M-w 3.9 x 10(4) g mol(-1) and that silver particles are stabilized by a single polymer molecule. For a polymer of M-w 1.2 x 10(4) g mol(-1), some aggregation occurs upon loading with the silver salt (AgNO3) and particle formation. Contrast variation experiments were performed employing different compositions of C6D6 and C6H6 in the solvent mixture. For the larger molar mass polymer a homogeneous distribution is found for the polymer/metal particle hybrides, whereas for the lower molecular weight polymer the metal particles are off-center.