Synthesis and electrochemical polymerization of 9,9-bis(carbazolylalkyl)fluorene and characterization of its conducting polymer film with high tensile strength

Free-standing poly(9,9-bis(carbazolylalkyl)fluorene) (P2Cz-A-F, alkyl = hexyl or dodecyl) films with high tensile strength (185–200 kg cm⁻²) were electrochemically synthesized by direct anodic oxidation of the monomer 9,9-bis(carbazolylalkyl)fluorene (2Cz-A-F) in a mixed electrolyte of boron trifluoride diethyl etherate containing 30% CH₂Cl₂ (by volume). The electrochemical and physical properties show that the quality of P2Cz-A-F films are much better than that of polycarbazole (PCz) and polyfluorene (PF) films due to the specially designed structure consisting of stiff bicarbazyl chromophores linked by a flexible long alkyl spacer at the fluorene unit. The structure of free-standing P2Cz-A-F films was investigated by UV–visible and infrared spectroscopy. Thermal analysis shows that the polymer films have good thermal stability. Fluorescent spectral studies indicate that polymer films in the solid state are blue-light emitters, which may meet potential applications in polymer light-emitting diodes.