Novel quaternary ammonium-functionalized diacetylenes: their synthesis and photopolymerization

In this paper, we report the synthesis of novel diacetylenes bearing trimethylammonium end groups, their photochemical polymerization and the spectroscopic characterization of the polymers by different techniques (UV–vis, fluorescence, FT-IR, Raman). The obtained results shed light on the role of the trimethylammonium head group (and its counterions) in the polymerization process. It is also demonstrated that the presence of an internal, H-bondable amide function in the diacetylene tail favors the photopolymerization process as well as the formation of the polydiacetylene in its blue, highly-conjugated form. Moreover, the corresponding polymer in the less-conjugated red phase, typical of polydiacetylenes in solution, shows significantly enhanced emission properties with respect to its counterparts carrying all-saturated lateral chains.