Synthesis and photoluminescence properties of thermal-stable polyfluorenes modified with adamantane derivatives as inserted-backbone units or chain ends

A series of modified polyfluorenes using 1,3-bis(4-bromobenzylideneanimo) adamantane and 4-bromobenzylideneanimo adamantane respectively as inserted-backbone units and chain ends were synthesized by Suzuki coupling polymerization. TGA and DSC determination reveal that the adamantane derivatives modified PFs are very thermally stable. The UV and PL spectra at room temperature reveal that the polyfluorenes modified by adamantane exhibit less chain aggregation compared with the homo-polymer PF6. Annealing effect tests of the polymer films revealed that the normalized intensities of green emission at 520 nm declined with the increase of the adamantane monomer feed content. These characteristics of the adamantane derivatives modified polyfluorenes could be owed to the bulky, rigid and thermal-stable molecular structure of adamantane.