Synthesis of symmetrical electroactive azobenzene compounds, their photoisomerisation and applications of thin films obtained by electropolymerisation

In the context of the present thesis, five new molecules with a symmetrical structure consisting of carbazole and azobenzene groups were synthesized, designed to fulfill their intended purpose, taking into account the unique structure-property relationship not found in the literature. Polymerization was achieved via the carbazole groups using the electrochemical polymerization method. The characterization of the obtained monomers was performed using Nuclear Magnetic Resonance Spectroscopy (1H-NMR, 13C-NMR) and Fourier Transform Infrared Spectroscopy (FT-IR). Polymeric structures were obtained using cyclic voltammetry, and the reduction and oxidation behaviors of the polymers were investigated. In addition, the changes in optical properties depending on the applied potential were investigated. In this context, the spectroelectrochemical, kinetic, colorimetric, and electrochromic properties of the obtained polymers were examined. The surface characterization of each polymer was performed using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and goniometer devices. The polymers formed from CzAzo-1 and CzAzo-2 monomers under a constant potential exhibited reversible color changes from colorless to magenta under different applied potentials. The colour changes of PCzAzo-1 and PCzAzo-2 were repeatedly reversed, and their surface properties were investigated. Their potential as a new class of electrochromic materials with repeatedly adjustable surface properties was highlighted. CzAzo-3, CzAzo-4 and CzAzo-5 monomers were successfully synthesised, and the structural and functional properties of the polymers obtained from these monomers were examined in detail, providing original contributions to the literature.