PREPARATION AND SYNCHROTRON X-RAY SPECULAR REFLECTIVITY STUDY OF LANGMUIR-BLODGETT-FILMS OF THE PHTHALOCYANINE [(C6H13)(3)SIO(SIPCO)(2)H]

The preparation by the Langmuir-Blodgett technique of multilayers of t he phthalocyanine [(C6H13)(3)-SiO(SiPcO)(2)H] (Si-Si Pc dimer) is desc ribed and compared with a similar compound, [(C6H13)(3)-SiOSiPcOGePcOH ] (Si-Ge Pc dimer), reported before. The Si-Si Pc dimer monolayer at t he air-water interface is stable on a pH = 7 buffered water subphase. The multilayer formed through Y-type deposition has a deposition ratio of I, assuming that the rings are parallel to the substrate surface. The film was studied by using synchrotron X-ray specular reflectivity experiments. The reflectivity profile obtained gives many Kiessig frin ges and two strong Bragg peaks, indicating that the multilayer obtaine d has a very good quality. The Bragg peaks correspond to a bilayer spa cing of 23.7 Angstrom and the average film density obtained from the K iessig fringes is 0.974 g/cm(3). The high degree of ring orientation a nd film perfection with the low film density give great advantages for the application of this phthalocyanine Langmuir-Blodgett film as gas sensors.