LANGMUIR-BLODGETT-FILMS OF METAL-COMPLEXES OF 4-(10,12-PENTACOSADIYNAMIDOMETHYL)PYRIDINE - A STRUCTURAL INVESTIGATION

Complex formation between 4-(10,12-pentacosadiynamidomethyl)pyridine a nd metal ions in the subphase results in stable Langmuir monolayers up to surface pressures of 35 mN m(-1). Electron microscopy pictures sho w a flat monomer monolayer before polymerization and a polymer monolay er exhibiting a more striated structure after polymerization. Multilay ers of the amphiphile can only be built up after complexation with met al ions. X-ray photoelectron spectroscopy (XPS) measurements definitel y confirm the presence of metal ions in the multilayers, and the molar ratio between metal and amphiphile is derived from the spectra. These multilayers are further characterized by means of small-angle X-ray r eflection measurements and Fourier transform infrared (FT-IR) spectros copy, which show that the amphiphile has a large tilt angle (a) with r espect to the surface normal. The multilayers are polymerized by means of UV irradiation, and UV-vis spectroscopy is used to study the polym erization process. The structural changes during polymerization are de duced from small-angle X-ray reflection measurements and FT-IR spectro scopy. In all cases, the bilayer spacing decreases during the polymeri zation process, whereas in some cases the regular plane of the all-tra ns conformation of the alkyl chains is converted to an irregular one c ontaining gauche conformations. For multilayers built up from a CuCl2- containing subphase, the whole distinct layer structure is destroyed d uring the polymerization process.