Low band gap conductive copolymer of thiophene with p-phenylenediamine and its magnetic nanocomposite: Synthesis, characterization and biosensing activity

Thiophene and p-phenylenediamine were utilized as monomers to prepare low band gap copolymer and nanocomposites with core-shell construction by a simple in situ emulsion polymerization. Different devices such as Fourier transform infrared, X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, dynamic light scattering and vibrating sample magnetometer (VSM) were used for characterizing the copolymer and nanocomposites. Band gaps were estimated from Cyclic voltammetry to be 2.1 - 1.7 eV for copolymers and nanocomposite. The results that obtained by measuring the conductivity with Four-probe method illustrated that the electrical conductivity of the nanocomposites is considerably higher than the copolymer which is dependent on the Fe content and doping degree. The nanocomposites showed superparamagnetic behavior with high-saturated magnetization (M-s = 10-16 emu/g). The direct electrochemistry of myoglobin (Mb) entrapped in the Nafion film on a glassy carbon electrode modified with synthesized nanocomposite had been investigated in this paper. Cyclic voltammetric results showed that a pair of well-defined quasi-reversible redox peaks appeared in the pH 7.0 phosphate buffer solution, which was ascribed to the direct electron transfer of Mb heme Fe(III)/Fe(II) redox couples. Also, the antioxidant activity of new nanocomposites was measured by using 2, 2-diphenyl-1-picrylhydrazyl assay. POLYM. COMPOS., 40:1034-1042, 2019. (c) 2018 Society of Plastics Engineers