SIZE-QUANTIZED CADMIUM-SULFIDE PARTICLES IN LANGMUIR-BLODGETT-FILMS -FILM THERMAL-STABILITY

The fabrication of particles in Langmuir-Blodgett films of cadmium ico sanoate and nonacosa-10,12-diynoate is followed using a quartz crystal microbalance. The mass changes accompanying the exposure of the film to hydrogen sulfide are consistent with a chemical reaction in the fil m which also produces the acid form of the surfactant. Film thermal st ability is greatly reduced after the particles are formed, a result al so consistent with formation of the more volatile acid form. The exten t of film removal by heating/outgassing suggests that particles are ca pped by adsorbed icosano or diynoic acid. It is likely that this cappi ng plays a role in particle growth control.