Synthesis and Induced Micellization of Pd-Containing Polystyrene-<i>block</i>-poly-<i>m</i>-vinyltriphenylphosphine Diblock Copolymers

Abstract

A novel type of chelating block copolymer, polystyrene-block-poly-m-vinyltriphenylphosphine (PS-b-PPH), was reacted with (CH3CN)2PdCl2 or (PPh3)2PdCl2, and the products were examined with FTIR, 31P NMR spectroscopy, and elemental analysis. The complexation of triphenylphosphine groups of these polymers with palladium compounds induces micellization in the system, and no polymer gels were formed. The morphology of the Pd-containing diblock copolymer micelles was studied with transmission electron microscopy (TEM). The size and kind of micellar aggregates depends strongly on the molecular weight of diblock copolymer, its composition, and metal compound type. Block copolymer-stabilized Pd nanoparticles were prepared by reduction of Pd-containing PS-b-PPH with N2H4·H2O, LiB(C2H5)3H, and LiAlH4 and analyzed by TEM, X-ray photoelectron spectroscopy, and wide-angle X-ray scattering techniques. It is found that the morphology of nanoparticles is controlled by the way of reduction and by the nature of the polymeric aggregates.