Electrochemical and AFM characterization of the electropolimerization of pyrrole over a graphite–epoxy resin solid composite electrode, in the presence of different anions

Mechanism and kinetics of the electrochemical formation of polypyrrole under forced convection conditions

“…Moreover, it is also possible to note that these small particles cover the whole electrode surface, see Figs. 9b and c. The electrochemical formation of Ppy clusters has also been observed, when potential steps were used to form Ppy on a carbon paste electrode [20] and when a voltammetric method was used to form Ppy onto a Pt electrode surface [8]. However, to the best of our knowledge such a well formed Ppy doughnuts-like structure have never been reported.…”

“…It is important to underline that Espinosa-Ramos et al [18], also found such a behavior after analyzing the experimental chronoamperometric curve recorded during the formation of passive layers of lead-base alloys sulfate. According to the experimental evidence obtained, in this research we propose to describe the experimental j-t curves recorded during the Ppy electrodeposition process over the vitreous carbon rotating disc electrode, by means of the sum of different contributions to the total current density (j total (t)), as has been described by Palomar-Pardavé et al [17][18][19][20][21][31][32][33][34][35][36][37], particularly in the work previously mentioned [18], Philipp and Retter [38] during the anodic film formation of thiourea at the mercury/electrolyte interphase, Scherbler et al [30] for nucleation and growth of poly(thiophene) and Rajagopalan and Iroh [26] during the development of polyaniline-polypyrrole composite coatings. Accordingly, we proposed one contribution, j oxi (t), due to the pyrrole oxidation on the vitreous carbon surfaces to form different oligomers in solution (see reactions (1)-(6)) or adsorbed on the electrode surface (see reactions (8)-(10)).…”

“…This perturbation results in a faradaic and/or capacitive reaction that gives rise to the formation of a new phase on the surface of the electronic conductor. Some examples of electrochemical processes that involve EPF are: electrodeposition of metals [17], anodic films formation [18], surfactant condensation or adsorption of micelles [19] and formation of conducting polymers [20][21][22][23].…”

“…The parameterized form of Eq. (13) is given by (20) j total ðtÞ ¼ P 1 t expðÀP 2 t 2 Þ þ P 3 ð1 À ð1 À expðÀP 2 t 2 ÞÞÞ þ P 4 ð1 À expðÀP 2 t 2 ÞÞ ð20Þ…”

Development of a Chloride Ion‐Selective Solid State Sensor Based on Doped Polypyrrole‐Graphite‐Epoxy Composite

“…The doped polypyrrole was electrochemically prepared using a BAS 100 potentiostat and the best experimental conditions reported in the literature [16,17]; it was grown in aqueous media over a stainless steel electrode; subsequently, the film formed is unattached from the surface for comminution into a powder by means of an agate mortar. The composite was then compounded by a 1 : 1 mix of epoxy resin:graphite þ polypyrrole; for other preparations the ratio remained constant, though only the relative polypyrrole and graphite quantities were varied.…”