|492. Zezin, A.A.; Feldmann, V.I.; Abramchuk, S.S.; Danelyan, G.V.; Dyo, V.V.; Plamper, F.A.; Müller, A.H.E.; Pergushov, D.V.: Efficient Size Control of Copper Nanoparticles Generated in Irradiated Aqueous Solutions of Star-Shaped Polyelectrolyte Containers, Phys. Chem. Chem. Phys. 17, 11490-11498 (2015) -- DOI: 10.1039/C5CP00269A|
The formation of copper nanoparticles (Cu-NPs) in irradiated aqueous solutions of star-shaped poly(acrylic acid) (PAA) were studied at two pH values. Transmission electron microscopy (TEM) demonstrates that the star-shaped macromolecules loaded with Cu2+ ions can act as individual nanosized containers and provide a perfect control over the size and size distribution of the Cu-NPs. Electron paramagnetic resonance (EPR) and optical spectroscopy show a transformation of mechanisms controlling the reduction of Cu2+ ions and the further Сu-NP formation. At pH 2.9, Cu-NPs are formed from the aquacomplexes of Cu2+ ions through homogeneous nucleation. At pH 4.3, the formation of Cu-NPs occurs inside macromolecular containers containing Cu2+ ions bound to carboxylic groups of the polyelectrolyte. In the latter case, the Cu-NPs apparently ripe from preformed Cu2O seeds which are thought to result from ultrasmall (Cu2+)m(OH-)k(COO-)n species, implying a heterogeneous nucleation.