Nanoparticulate copper - routes towards oxidative stability

A modified polyol-based reduction method in ethylene glycol that incorporates poly( N -vinylpyrrolidone) (PVP, M av = 10 000; 40 000; 55 000) as polymeric anti-agglomerant alongside a reducing additive (N 2 H 4 ·H 2 O, NaBH 4 , NaH 2 PO 2 ·H 2 O) has been employed to investigate the influence of synthetic parameters on the purity, morphology and stability of an array of polymer-coated copper nanoparticles. While data point to ethylene glycol being capable of acting as a reductant in this system, the use of NaH 2 PO 2 ·H 2 O as co-reductant in tandem with the presence of PVP ( M av 40 000) has rendered nanoparticles with a mean size distribution of 9.6 ± 1.0 nm that exhibit stability towards oxidation for several months. These data allow us to probe fundamentally how oxidatively stable nano-copper might be achieved. By treating copper salts in ethylene glycol and poly( N -vinylpyrrolidone) with a reducing additive we modulate the purity, morphology and oxidative stability of the resulting polymer-coated copper nanoparticles.