Preparation of concentrated stable dispersions of uniform Ag nanoparticles using resorcinol as reductant

Uniform silver nanoparticles ranging in size from 12 to 80 nm were prepared by reducing silver ammonia complex with resorcinol in presence of Arabic gum. Despite the high ionic strength of the system, the precipitation process yields stable dispersions at metal concentrations as high as 4.0 wt% (0.38 mol dm(-3)). Stable dispersions with higher solids concentration up to 20 wt% silver (1.9 mol dm(-3)) were obtained by subjecting the 'as precipitated' dispersions to ultrafiltration. The effects of reaction parameters (pH, concentration of reactants, metal/stabilizer ratio, and temperature) on particle size and dispersion stability are discussed and a mechanism for the reduction of silver is proposed. (C) 2016 Elsevier Inc. All rights reserved.