INTERFACIAL COMPLEXATION OF PHOSPHOLIPID LANGMUIR MONOLAYERS WITH WATER-SOLUBLE PORPHYRINS AND PHTHALOCYANINES - AN X-RAY REFLECTIVITY STUDY

The use of Coulombic forces to isolate charged, water-soluble macrocyc les at the air-water interface (through their interactions with the op positely charged headgroups of a phospholipid Langmuir monolayer) is c urrently being exploited in this laboratory as a means to create two-d imensional arrays of pigments. Significant differences have been obser ved in the surface pressure-molecular area (pi-A) isotherms of dihexad ecyl phosphate on subphases containing either copper (II) tetra-(methy laza)-phthalocyanine or tetra-(methylpyridyl)-porphyrin, both of which are cationic. In-situ X-ray specular reflectivity has been employed t o determine interfacial organization in these systems and to elucidate the origin of their different phase behavior at the air-water interfa ce.