SILVER COLLOIDS AND MACROEMULSIONS OF METAL INTERFACIAL COLLOIDAL FILMS - INTERACTION WITH DITHIZONE

We discuss macroemulsions stabilized by silver interfacial colloidal f ilms and the effect of dithizone on them. These emulsions are characte rized by a very sharp size distribution. We find that dithizone, which is known for its strong interaction with silver, strongly affects the state of flocculation of the colloid. The size of the flocs can be re lated quantitatively to the droplet size. Dithizone also affects the r ate of nucleation of the colloid, which is also expressed in a measura ble reduction in the droplet diameter. The adsorption of dithizone on silver hydrosols and organosols and its spectroscopy are also studied. Using Raman spectroscopy, we find that dithizone adsorbs on hydrosols in a structure similar to that of silver dithizonate. S-atom and azo- N-atom bonds with silver are formed in an end-on, perpendicular orient ation. In the interfacial colloid the dithizone is present predominant ly in a disulfide form.