LANGMUIR-BLODGETT-FILMS OF POLY(O-ANISIDINE)

LB films have been fabricated by transferring poly(o-anisidine) (POA) monolayers from a pure water surface onto glass substrates using the conventional dipping method. The chemically synthesized poly(o-anisidine) consists of two fractions, one containing mainly octamers and another of high molecular weight (around 28000 g/mol). The low weight fraction forms condensed Langmuir monolayers which are anchored to the water surface through one single group, probably the metoxy-aniline, yielding an area per molecule of ca. 20 angstrom2. The molecular configuration in the high-weight fraction monolayers appears to be such that one in each four or five segments of the polymer chain makes contact with the water. UV-visible spectra were obtained for the HW fraction LB films which were identical to those of POA in solution, changing from dark blue to green when the film is exposed to HCl vapour. Preliminary conductivity measurements were carried out on these LB films showing that the conductivity increases by three orders of magnitude upon exposure to HCl vapour.