Nonaqueous electrophoresis reveals that the electrokinetic potential of CdS nanoparticles increases slightly (85 - 120 mV) along with the concentration (0-5 × 10-3 M) of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in n-decane, while negatively charged SiO2 particles acquire positive charge (switching from -75 up to +135 mV). The energies of interparticle interactions in CdS - CdS and CdS - SiO2 systems are calculated from these parameters and the literature values of the Hamaker constants according to the Deryaguin - Landau - Verwey - Overbeek (DLVO) theory. It is concluded that the presence of a minimum (2.5 kBT) on the potential dependences of the CdS-SiO2 system indicates the formation of CdS-SiO2 aggregates electrostatically bound by heterocoagulation at low concentrations of AOT. The luminescent properties of the obtained ultrafine CdS-SiO2 powders depend on the CdS content.
- cadmium sulfide
- DLVO theory
- electrophoretic concentration