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Oxidative polymerization of p-aminoazobenzene in acetonitrile

1991; Elsevier BV; Volume: 315; Issue: 1-2 Linguagem: Inglês

10.1016/0022-0728(91)80067-z

2590-2954

H. A. Abd El‐Rahman, Takeo Ohsaka, Fusao Kitamura, Koichi Tokuda,

Electrochemical Analysis and Applications

The oxidative polymerisation of p-aminoazobenzene (PAAB) on glassy carbon in acetonitrile was studied by cyclic voltammetry, the potential step method, and SEM and FT-IR spectroscopy. The presence of a base-like pyridine was found to be essential for the polymerization process. The prepared polymer (poly(p-aminoazobenzene), abbreviated as poly-PAAB) films of thicknesses up to several (μm were found to be very stable and insoluble in aqueous solutions and in common organic solvents, except dimethyl formamide and tetrahydrofuran. The films are electroactive in acidic solutions but electroinactive in acetonitrile. The electroactivity of these films is attributed to a proton + electron addition/elimination reaction at -NH- sites. The capacitive current contribution in the potential region where the films are electroactive is larger than is usually observed for the conventional polyaniline films. The concentration of the electroactive sites in poly-PAAB was found to be about twenty times lower than that of polyaniline while the diffusion coefficient for the charge transport process within the films was found to be four times lower. The azo groups presented in the films were found to be reduced irreversibly in acetonitrile and aqueous acidic solutions. The prolonged reduction of the azo groups was found to lead to the loss of the electroactivity and the slow degradation of the films.