Copper Phthalocyanine-Mica Interactions in Nonaqueous Media

The interaction forces and adhesion of copper phthalocyanine particles with a mica substrate in isoparaffin were directly measured using an atomic force microscope. The study was conducted primarily to investigate the stabilization mechanism of copper phthalocyanine dispersions in a nonaqueous medium. The nature of the forces was examined in the presence of various concentrations of water and zirconium octanoate, both of which are present at the particle-isoparaffin interface. A weak attraction, as well as a small adhesion, exists between the copper phthalocyanine particles and the mica surface. These interactions are a function of the water content of the hydrocarbon phase and appear to be a result of capillary forces. The addition of zirconium octanoate produces significant short range repulsive forces with no adhesion between the copper phthalocyanine and mica surfaces. The shape of the force against distance curves suggests that the dispersion stability of the copper phthalocyanine arises through steric stabilization by adsorbed zirconium octanoate. The same qualitative interaction behavior was observed when the copper phthalocyanine particle was coated with a layer of polyvinyl acetate latex. Copyright 1999 Academic Press.