Polymerization of modified diacetylenes in Langmuir films

The polymerization of a series of diacetylene Langmuir monolayers modified in the hydrophobic as well as in the hydrophilic part of the molecule was s tudied by measuring the kinetic changes of the mean molecular area and UV-v is spectra. The polymerization properties of the monolayers were dependent on the position of the diacetylenic unit and whether an ester or sulfonyl g roup was introduced in the hydrocarbon chain. The substances containing a s ulfonyl group showed the highest polymerization activity. The blue-to-red t ransition usually observed for diacetylenes in Langmuir and Langmuir-Blodge tt films due to UV irradiation was not observed, instead the studied substa nces formed directly a red form polydiacetylene. A first-order consecutive reaction kinetic model with a steady-state approximation was successfully a dapted to the experimental results of three of the studied compounds.