Eletrossíntese e caracterização de novos materiais derivados de 4-anisidina

Abstract

In this paper we report the electropolymerization of 4-anisidine in a acid and basic medium over graphite electrodes, gold electrode, gold electrode on quartzo and graphite electrode bar obtained by cyclic voltametry. The properties and characterization of the materials were performed by electrochemical methods (cyclic voltametry, electrochemical quartz crystal microbalance and electrochemical impedance spectroscopy) and spectroscopy (infrared by Fourier transform, uv-visible and fluorescence), thermal analysis (thermogravimetric analysis and differential thermogravimetric analysis), microscopic (scanning electron microscopy and atomic force microscopy) and X-ray diffraction. It is possible to form polymers in acidic and basic medium on the different electrodes used. The cyclic voltammetry carried out after the electropolymerization solution containing the suport electrolyte, and anode or cathode probes confirm the modification of electrodes. Therefore its observed variations of voltammetric profile obtained compared of profile before modification of the electrode, both for the current values and the displacement of oxidation and reduction peaks, proving the difference of the materials obtained. The polymer obtained in acid medium poly(4-ANA) has characteristics of a conductive polymer and polymer obtained in alkaline medium poly(4-ANB) has insulating characteristics, these results are confirmed by electrochemical impedance spectroscopy. The results obtained by electrochemical quartz crystal microbalance indicate that the poly (ANB) is electropolymerized in greater quantity and more evenly than poly(4-ANA), this is confirmed by the micrographs obtained by scanning electron microscopy, atomic force microscopy and optical microscopy of the modified electrodes. The UV-visible spectroscopy and fluorescence indicate that poly(4-ANA) presents greater degree of conjugation than poly(4-ANB). The results of thermal analysis indicate that the polymeric materials obtained are more stable than the 4-anisidine. By X-ray diffraction patterns, it was observed that 4-anisidine and polymeric materials have obtained structure with crystalline character. The infrared spectra show that in both cases, the polymer is formed by the nitrogen atom.