Self-encapsulation of poly-2,7-fluorenes in a dendrimer matrix

The synthesis and characterization of complex dendritic, rigid rod poly-2,7 -fluorene homopolymers and copolymers via a macromonomer approach is report ed. Several 2,7-dibromofluorene monomers containing benzyl ether dendrons ( generations 1, 2, and 3) in the 9,9 ' -position of the fluorene ring were p repared and employed in condensation polymerizations to yield both homopoly mers and copolymers with diethylhexylfluorene. Fluorescence measurements of the materials reveal extensive conjugation along the polymer backbone. The determination of the solid-state PL spectra and quantum efficiencies showe d that there is an apparent optimum size of the dendritic side groups with the [G-2]-derivatives showing high reactivity with associated site isolatio n of the conjugated chain. AFM analysis and DSC results confirmed that the hybrid polymers and copolymers did not shaw any sign of a microphase-separa ted morphology. First EL-results demonstrated that the homopolymers have hi gher turn-on voltages then the corresponding copolymers.