Structural and electrical studies of alternating layers of porphyrins and fatty acids

Langmuir-Blodgett multilayers were formed by the alternate deposition of amphiphilic derivatives of mesoporphyrin IX and protoporphyrin IX and of various fatty acids. These films were studied by low angle X-ray diffraction, scanning electron microscopy and by conductivity measurement in the plane of the film. It is shown that, in the case of diol porphyrin derivatives, a well-ordered superlattice is produced. In contrast, the use of diesters leads to the segregation of the two materials in the plane of the film. Such segregation implies the diffusion of molecules after deposition over distances of the order of 1 μm.