Experimental study of platinized poly-2,5-dimethoxyaniline electrodes

In the domains of chemical catalysis and analytical chemistry, the modification of metal electrodes by the deposition of multilayers was developed about twenty years ago. The purpose of our work was to compare the behavior of an electrode prepared with a substituted polyaniline with that of electrodes regularly used in analytical chemistry: platinum, platinized platinum and glassy carbon. We initially present results obtained with poly-2,5-dimethoxyaniline (PDMAn) on two classic systems: the couple Fe(CN)(6)(3-)/Fe(CN)(6)(4-) and the couple O-2/OH-. The first example is often studied during training in electrochemistry because of the good results generally obtained. Levich's equation is effectively well verified. On the other hand, reduction of oxygen and oxidation of OH- ions are always limited by the rate of the electron transfer reactions. It seems to us that the study of the behavior of these two systems with platinum electrodes covered with PDMAn, platinized or not, could be interesting. The oxidation of isopropanol in a weakly acid medium was also investigated. In the field of analytical chemistry, a more detailed study is mandatory before deciding on the possibility of using electrodes modified with films of substituted polyaniline. An electrode, which would not be platinized, does not seem useful; the use of electrodes prepared with platinized polymers deposited on substrates less expensive than platinum, (glassy carbon for example), may be more interesting. It seems that H2O2 formation over a wide domain of potential would be the best result for oxidations and new experiments will be investigated. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.