Development of light-emitting liquid-crystalline polymers with a pentafluorinated bistolane-based luminophore†
Herein, the synthesis and evaluation of light-emitting liquid-crystalline (LELC) polymers bearing a pentafluorinated bistolane-based luminophore are reported. Methacrylate monomers, prepared in five steps from readily available 4-alkoxy-substituted phenylacetylene derivatives, were subjected to radical polymerisation to produce polymers with 10–23 repeating units with 48–89% yields. The polymers possess a high thermal stability of up to 353 °C and display a smectic (Sm) LC phase over a broad temperature range. They also exhibit a photophysical behaviour, whereby they demonstrate intense photoluminescence (PL) in the solution and pristine powdered solid states. These PL emissions can be shifted from blue to light blue by modulating the length of the flexible alkylene-linkage. Interestingly, the LELC polymer materials exhibited PL even in the Sm phase, and the PL colour changed from blue to light-blue via a thermal phase transition.