Low molecular weight compounds as effective dispersing agents in the formation of colloidal silver nanoparticles

A convenient method to synthesize uniform, well-dispersed colloidal silver nanoparticles is described. Aldonic acid or α-hydroxy acid compounds of low molecular weight are used instead of polymeric compounds as dispersing agents to prepare silver nanoparticles. The size, conformation, and electrical conductivity of the silver nanoparticles, and the effect and function of the dispersing agents are investigated in detail. Using these low molecular weight compounds as dispersing agents, silver nanoparticles with a diameter of 10 nm or less and high electrical conductivity can be obtained. In addition, this procedure allows silver nanoparticles to be sintered at 150 °C, which is lower than that required for silver nanoparticle formulation using polymeric compounds (200 °C). The silver nanoparticles produced by this process can be used to prepare various inks and to manufacture electronic circuits. It is found that low molecular weight compounds are more effective dispersing agents than polymeric compounds in the formation of silver nanoparticles.