Triple Complexes of Bismuth Nanoparticles with β-Cyclodextrin and Polyvinylpyrrolidone

Ternary complexes of bismuth nanoparticles with β-cyclodextrin and polyvinylpyrrolidone are studied via UV and visible spectroscopy and dynamic light scattering. It is shown that, depending on the ratio of the concentrations of β-cyclodextrin to polyvinylpyrrolidone in a synthetic medium, bismuth nanoparticles can be stabilized sterically either by distributing polyvinylpyrrolidone molecules over the surface of a complex of nanoparticles with β-cyclodextrin or by forming inclusion complexes of nanoparticles in the hydrophobic cavity of β-cyclodextrin as a result of associated β-cyclodextrin molecules being pushed apart by polyvinylpyrrolidone molecules. The conditions are determined for the formation of ternary complexes that are aggregatively stable for 20 days and are characterized by a unimodal particle size distribution.