Dispersion mechanisms of Arabic gum in the preparation of ultrafine silver powder

Abstract

Finely divided silver micro-spheres were prepared with Arabic gum (AG) as dispersant through the chemical reaction of AgNO3 and ascorbic acid. AG dispersive mechanisms in the preparation of silver powder are proposed in the paper. The -COOH and -NH2 groups of AG reacted with Ag+ to form Ag+-AG complexes, followed by the nucleation of silver on AG polymer chains, which yielded silver spheres with an AG protection layer by reducing Ag+-AG complexes with ascorbic acid. With the steric effect of AG, the prepared silver particles exhibit improved dispersibility. UV-Vis and FTIR spectra confirmed that silver particles were stabilized by AG.