抄録
The growth mechanism of CdS ultrafine particles in water-in-oil microemulsions was investigated. The growth occurs via a irreversible particle coagulation process. Its rate constant is dependent on the agglomeration number of a particle n. At small agglomeration numbers, the rate constant k is about 107 dm3mol–1s–1. It decreases dramatically to about 103 dm3mol–1s–1 at a critical agglomeration number nc followed by a further decrease in k above 2nc. This causes sharpening of the size distribution near nc and 2nc. A simple model based on the coagulation process with n-dependent rate constants is proposed, which explains well the experimental results. The effects of initial mixing and the feed ratio of Cd2+ to S2– are understood well by the proposed model. The relationship between nc and the stable supramolecules composed of CdS particles was discussed.
