文摘
A polymer (poly(9,10-anthracenevinylene-alt-4,4'-(9,9-bis(4-(4'-(1,2,2'-triphenylvinyl)phenoxy)butyl)-9H-fluorene-2,7-diyl) dibenzaldehyde), P1 was successfully synthesized through the Wittig-Horner reaction by employing fluorene and 9,10-distyrylanthracene moieties as building blocks for backbone and tetraphenylethenes as pendant groups. Photophysical and thermal properties of the resulting polymeric emitter were fully characterized by ultraviolet-visible (UV-Vis) absorption and photoluminescence (PL) spectra, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). While P1 emits an orange-light centered at 567 nm in dilute tetrahydrofuran (THF) solution, the solid powder of the polymer exhibits strong yellow emission peaked at 541 nm. It is also found that the as-synthesized polymer shows unique property of aggregation-enhanced emission (AEE). In addition, P1 possesses high thermal stability with a decomposition temperature (Td,5% of 430 °C and high morphological stability with a glass transition temperature (Tg of 171 °C. Under the stimulus of mechanical force, the emission of P1 can be changed from yellow to red (Δλmax = 61 nm), showing a remarkable mechanochromism. The results from XRD analysis suggest that such mechanochromic phenomenonof P1 is probably caused by the destruction of crystalline structure, which leads to the conformational planarization of the distyrylanthracene moieties forming by the polymerization and the increase of molecular conjugation of the backbone.
