Brewster angle microscopy and surface potential measurements of Langmuir-Blodgett films of zinc tri(tert-butyl)-4-sulphophthalocyanine

The formation of a Langmuir monolayer of an amphiphilic derivative of zinc phthalocyanine (Na[ZnPctSO3]) has been studied by means of surface potential technique and Brewster angle microscopy. The experiments were undertaken in order to understand the behaviour of this monolayer with a well-defined surface pressure isotherm. The floating film is described as a truly monomolecular layer formed by very rigid islands in which the phthalocyanine units tend to take on a preferential orientation with their planes perpendicular to the air-water interface, for high values of the surface pressure.