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

In the domains of chemical catalysis and analytical chemistry, the modifica tion of metal electrodes by the deposition of multilayers was developed abo ut twenty years ago. The purpose of our work was to compare the behavior of an electrode prepared with a substituted polyaniline with that of electrod es regularly used in analytical chemistry: platinum, platinized platinum an d glassy carbon. We initially present results obtained with poly-2,5-dimeth oxyaniline (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 tr aining in electrochemistry because of the good results generally obtained. Levich's equation is effectively well verified. On the other hand, reductio n 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, platiniz ed or not, could be interesting. The oxidation of isopropanol in a weakly a cid medium was also investigated. In the field of analytical chemistry, a m ore detailed study is mandatory before deciding on the possibility of using electrodes modified with films of substituted polyaniline. An electrode, w hich would not be platinized, does not seem useful; the use of electrodes p repared with platinized polymers deposited on substrates less expensive tha n platinum, (glassy carbon for example), may be more interesting. It seems that H2O2 formation over a wide domain of potential would be the best resul t for oxidations and new experiments will be investigated. (C) 2001 Academi e des sciences / Editions scientifiques et medicales Elsevier SAS.