Electrochemical Synthesis, and Electrochromic Properties of Poly(2-(9H-Carbazol-9-yl)acetic acid) Film

A poly(2-(9H-carbazol-9-yl) acetic acid) thin-film was formed on the surface of a platinum (Pt) electrode by oxidative electropolymerization of a new carbazole derivative. Electrochemical polymerization was performed in reaction medium containing monomer and 0.1 M TBABF4 mixture in acetonitrile (ACN) using repeated cycling at a scanning rate of 250 mV. The electrochemical polymerization of 2-(9H-carbazol-9-yl) acetic acid (25mM) was studied using cyclic voltammetry on both Pt and ITO electrodes. The structure of the soluble polymer was elucidated by nuclear magnetic resonance (1H and 13CNMR) and Fourier transform infrared (FTIR) spectroscopy. The weight average molecular weight of poly(2-(9H-carbazol-9-yl) acetic acid) was determined using gel permeation chromatography (GPC) and found to be 130900 g/mol. Characterizations of the resulting polymer were performed by cyclic voltammetry, dry conductivity measurement and scanning electron microscopy (SEM), while the UV-Visible spectroscopy and electrochemical spectroscopic studies indicated that the poly(2-(9H-carbazol-9-yl) acetic acid) film showed a green color in the oxidized state, and high transmittance in the neutral state. Moreover, the poly(2-(9H-carbazol-9-yl) acetic acid) film is soluble in common organic solvents, such as DMSO, THF, NMP, and DMAC. The conductivities of poly(2-(9H-carbazol-9-yl) acetic acid) is about 4.3x 10-2 S/cm.