engleski

The Influence of OPDA Additions to PANI Layers Characteristics

In this work the influence of ortho-phenylenediamine (OPDA) addition in the process of aniline polymerisation has been examined. The electrochemical polymerisation of the layer was carried out by means of cyclic voltammetry. The study of PANI layer characteristics were carried out on two substrates: Pt- and stainless steel electrode. The investigations on Pt-electrode were carried out for the layer obtained from 0.1M aniline with the addition of 1 and 5 mM of OPDA, all in 3 M phosphoric acid solution. The characteristics of the obtained layer were investigated by examining the catalytic effect of the different layers on H2Q/Q test redox system by means of RDE voltammetry. It was found that there is present a catalytic effect on the potential of H2Q/Q redox reaction, but the resulting limiting current decreases as the addition of OPDA increases, indicating that lower density of active centres, necessary for the catalytic oxidation, is available. The investigations on steel electrode (13% Cr) were carried out on a layer resulting from the polymerisation of 0.5M aniline with the addition of 5, 10 and 50 mM of OPDA. The layer was tested in Cl- solution by monitoring the open circuit potential (OCP). It was shown that, with the increase of OPDA addition, the time at OPC is prolonged. The AFM micrographs show the difference in morphology when OPDA is added, suggesting that OPDA additions cause the increased compactness of the polymer layer.

modified polyaniline; ortho-phenylenediamine; catalysis; and corrosion protection

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