SELF-ASSEMBLED LAYERS OF SUBSTITUTED POLY(P-PHENYLENE)S ON GOLD AND COPPER INVESTIGATED BY SOFT-X-RAY SPECTROSCOPY

Near edge X-ray absorption fine structure spectroscopy (NEXAFS) was us ed to investigate the adsorption of self-assembled substituted poly(p- phenylene)s on gold and copper surfaces from solution. While on gold o nly films with thicknesses in the monolayer range were found, on coppe r ''thick'' layers were also detected. The properties of the films dep end on the chemical structure of the molecules and the immersion time of the substrate in solution. The determined mean tilt angles of the p henyl rings in the rigid polymer backbone and side chains indicate tha t the influence of the substrate on the orientation is strongest for t hin films on gold and copper and diminishes for thick films on copper. , Interaction of polymers with the substrate was found to occur via th e pi-system of the phenyl rings. In the case of ''thick'' layers, the distinction between adsorbate and substrate becomes ill-defined, sinc e there appears to be strong evidence for the presence of organometall ic complexes in a long-ranging graded interphase.