Direct synthesis of coated gold nanoparticles mediated by polymers with amino groups

► We report the use of copolymers as reductant and stabilizer to obtain gold sols. ► Polymer structure effect on the gold sols formation was established. ► Gold reduction depended on the aqueous dissociation equilibrium of amino groups. ► Electrochemical redox potentials dictate the reductant activity of polymers. ► Sigmoidal nanoparticle growth kinetics was observed.