Synthesis, characterization and photoluminescence study of novel sulfobetaine polyelectrolytes

A novel sulfobetaine copolymer is developed via polycondensation approach. The comonomers, melamine, condenses with a diketone, 5,5-dimethyl-1,3-cyclohexane (dimedone) to produce polyimine chain based on Schiff base chemistry. Dimedone-[N,N' melaminium] propane sulfonate copolymer crystals were obtained on treatment of the polyimine with sulfopropylating agent, 1,3-propane sultone with a crosslinker, di(ethylene glycol diacrylate) (DEGDA). This crosslinked sulfobetaine polymer yielded fine needle like single crystals and shows strong blue fluorescence and a week green phosphorescence. Multi-exponential fluorescence decay function indicates the presence of different conformers both in solution and crystalline phase. This easy straightforward protocol for synthesis of crystalline, soluble, and luminescent polymer could prove to be a landmark in development of next generation smart functional materials.