The formation of silver halide sols in the presence of cationic detergents

Abstract

The influence of cationic detergents on the formation of negative sols of silver chloride, silver bromide, and silver iodide has been studied by means of spectrophotometry, microelectrophoresis, and electron microscopy. As cationic detergents, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, bromide, and iodide, and dodecylquinolinium bromide were employed; these were all pure compounds. All the detergents studied gave “sensitized” coagulation of the silver halide sols; critical coagulation concentrations of the order of 10 −5 M were obtained with sol concentrations of 1 × 10 −4 M and 5 × 10 −4 M. With silver bromide, using dodecyltrimethylammonium bromide and dodecylpyridinium bromide periodic coagulation and stabilization of the sols was observed. A similar phenomenon was observed with dodecylpyridinium iodide and silver iodide, but with dodecylpyridinium chloride-silver chloride and dodecylquinolinium bromide-silver bromide only one coagulation region was found. The mechanism of sol formation in the presence of detergents is discussed and an interpretation is given of the results obtained.