Synthesis, processability and photoluminescence of pyrene-containing polyimides

Four different contents of pyrene group were introduced in polyimide (PI) backbone via one step polycondensation procedure. The chemical structure, thermal property, process ability, and photophysical performance of polymers were characterized and analyzed. The obtained PIs exhibited high glass-transition temperatures from 270 to 285 °C, and weight remainder rates of PIs were all above 50% at 800 °C in N2. Fluorescence detection of metal ions was taken by adding Cu2+, Pb2+, Cr3+, Cd2+, Fe3+, Co2+, and Ni2+ to polymer solutions. It was interesting to found that the polymer exhibited significant luminescence emission “turn-on” response to Cu2+ and fluorescence emission quenching to Fe3+. Furthermore, the uniform morphologies of pyrene-containing PI fibers were prepared via electrospinning technique for investigating their optical properties in solid state. The fluorescent images and optical photographs indicated that the luminescence stability of polymers in fiber solid state was decided by both the chromophore in macromolecular chain and effective draft of polymer chains during spinning process. This study provided a facility strategy for controlling the morphology structure of materials and keeping the PL emission intensity in flexible devices.