Preparation of silver colloid and enhancement of dispersion stability in organic solvent

Silver colloid of nanometer size was prepared in liquid phase by a reduction method. AgNO3, FeSO(4)(.)7H(2)O, and Na(3)C(6)H(5)O(7)(.)2H(2)O were used as silver precursor, reducing agent and dispersing agent, respectively. As precursor concentration was decreased or the concentration of dispersing agent was increased, the prepared particle size was decreased from 180 rim to 20 rim. Apparently, the particle size seemed to be decreased with the increase of stirring rate, but it was confirmed by TEM that the size of primary particle remained the same. This result indicates that the uniformity of precursor concentration in the reactor affects the particle size and the stirring rate should be kept higher than the critical value to prevent the agglomeration of particles. In order to make the dispersion stability of the prepared silver colloid maintained even in non-polar organic solvent, electrodialysis technique was applied. As ionic species in colloidal solution were removed by electrodialysis, the dispersability of the colloid in the organic solvent of long carbon chain was confirmed to be increased. (C) 2004 Elsevier B.V. All rights reserved.