PHOTOREACTIVE THIN FILMS OF AZOBENZENE-DERIVATIZED POLY(AMIC ACID) AND POLY(IMIDE) LANGMUIR–BLODGETT–KUHN MULTILAYER ASSEMBLIES

Abstract

Various poly(amic acid)s with azobenzene-chromophore sidegroups have been synthesized and structurally and functionally characterized. Their amphiphilic properties allowed us to prepare stable monomolecular layers at the water/air interface of a Langmuir trough, and to transfer these highly organized monolayers to solid supports via the Langmuir–Blodgett–Kuhn deposition protocol. The resulting multilayer assemblies were investigated by surface plasmon- and waveguide-optical techniques, by X-ray reflectometry, and by UV-vis and IR spectroscopies. Thermal imidization of the assemblies resulted in functional poly(imide) multilayers that still could undergo photoisomerization reactions in their azobenzene sidegroups. The kinetic parameters of this trans-cis and cis-trans isomerization, respectively, as well as, the resulting control of the alignment of a liquid crystal in contact to these "command layers" were evaluated.