Preparation and Characterization of poly(Azomethines) Containing Ether and Methylene Bridges: Photophysical, Electrochemical, Conductivity and Thermal Properties.

Abstract

In this paper, a series of polyazomethines (PAZs) were prepared using dihydroxy substituted Schiff bases and 1,4-diiodobenzene. Also, different group effect such as methylene carbon and etheric oxygen bridges on photophysical, electrochemical, conductivity and thermal properties were clarified. The new polymeric materials structures were confirmed by means of 1H-NMR, FT-IR and UV-vis measurements. The molecular weight distributions of polymers were determined with gel permeation chromatography (GPC) measurements. Photophysical behaviors of polymers were explored by UV-vis absorption and fluorescence measurements. TGA-DTA and DSC techniques have been used for the thermal characterization of the PAZs. Thermal data and fluorescence measurements showed that etheric oxygen bridge containing polymers have a bit higher char and emission intensity than the methylene carbon bridge carrying polymers. According to TG analysis, Ton values of P-2MPDP, P-2-OPDP, P-4-MPDP and P-4-OPDP were found as 210, 250, 249 and 233°C, respectively. The HOMO-LUMO energy levels, electrochemical (E' g ) and optical (E g ) band gaps were calculated from cyclic voltammetry (CV) and UV-vis measurements, respectively. The electrochemical (E g ') band gaps values of P-2MPDP, P-2-OPDP, P-4-MPDP and P-4-OPDP were calculated as 2.68, 2.32, 2.34 and 2.07, respectively. Additionally, four-point probe technique was used to measure solid state electrical conductivities of both doped and undoped states of the PAZs.