POLYMERIZATION OF DIACETYLENES IN MULTILAYERS

In the reported experiments, a series of amphiphilic diacetylene monocarbonic acids was synthesized, and their ability to form monolayers at the air-water interphase was investigated. Acids with total number of C atoms greater than equivalent to 20 and mp greater than 45 degree C form surface states suitable to be used for buildup of multilayers by the Langmuir-Blodgett technique. Using the LB technique, multilayers of defined thickness were built up on quartz substrates. The multilayers were polymerized by exposure to a UV light source according to the mechanism of solid-state polymerization of diacetylenes without destruction of the layer structure and with retention of the packing in the individual layers. Thus well-defined polymer multilayers were obtained. The monomer and polymer multilayers were characterized by UV spectra, x-ray small-angle diffraction, and interference microscopic and electron microscopic techniques. The polyconjugated backbones of the polymer chains are all stretched out in the plane of the substrate but not over macroscopic dimensions because the multilayers have a crystalline domain structure. The polymer multilayer films are quite stable under ambient conditions.