Surface properties and electrochemical synthesis of carbazole derivative polymers

Abstract

In this study, carbazole-derived polymers were synthesized on ITO (indium tin oxide)-coated PET (Polyethylene terephthalate) via electrochemical reactions and conductivity measurements of the resulting polymeric films depending on temperature were actualized via four-point probe system. Their characterization processes were carried out by UV, FT-IR, NMR, TG-DTG, SEM analyses. Spectroelectrochemical measurements were performed for investigating their electrohromic properties. Homopolymer (P-6C) of carbazole-derived monomer as well as copolymer with thiophene were obtained by electrochemical polymerization method. Based on the CV measurements taken, the resulting copolymer film had good stability on the electrode surface. According to the thermal analysis of the homopolymer, its final degradation temperature was 297 °C and its residue amount at 800 °C was calculated as 18%. Comparisons of conductivity measurements were made depending on the temperature of the polymer films (25, 50 and 90 °C). The electrical conductivity values of the thiophene-carbazole derivative copolymer (6C-T) were decreased depending on the temperature (13.7 S/cm at 25 °C, 1.99 × 10^–2 S/cm at 90 °C). The conductivity of carbazole derivative homopolymer product (P-6C) was recorded to increase 10 times with increasing temperature. In the SEM image of P-6C a large and small, non-homogeneous surface with rounded corners was observed. Also, in the SEM image of the copolymer with thiophene (6C-T), small structures with rounded corners originating from thiophene and a non-homogeneous flat surface were seen. As a result, it has been revealed that the copolymer obtained from thiophene and carbazole derivatived compound could be used as a component in electronic devices due to its high conductivity value.

Graphical Abstract