Effect of Low-Temperature Treatment of Silver Hydrosol on Its Absorption Spectra

Absorption spectra of a stable silver hydrosol before and after low-temperature treatment were recorded and analyzed. An increased duration of this treatment leads to linear decrease in volume concentration of Ag particles having an absorption maximum _max = 412 nm and to the formation of a new fraction of larger particles. It was shown on the basis of calculation of spectra by the Mie theory and the theory of plasmon resonance absorption that the low-temperature treatment of hydrosol does not change the electron density of metal particles and the number of surface defects. The effect of low-temperature treatment is independent of sol concentration. The particle aggregation under low-temperature treatment conditions is favored by the preliminary adsorption of p-phenylenediamine derivative.