Rosa C.D. Peres

The role of ion exchange in the redox processes of polypyrrole/dodecyl sulfate films as studied by electrogravimetry using a quartz crystal microbalance

Abstract The electrochemical redox mechanism of a dodecyl sulfate-doped polypyrrole was studied in detail by electrogravimetry using a quartz crystal microbalance. In order to distinguish the nature of the inserted/deinserted species, different salts were used as aqueous electrolytes. A quantitative analysis of the results indicated that the surfactant counter anion was trapped in the polymer matrix and that both anions and cations of the electrolyte play an important role in the redox processes. Quantitative calculations showed that the hydration sphere of these ions must be taken into account when dealing with the redox processes of conductive polymers adhered to the surface of electrodes.

Electrochemical study of polypyrrole/dodecyl sulphate

Abstract The electropolymerization reaction of pyrrole in the presence of sodium dodecyl sulphate has been studied and the electroactivity of the polymer investigated with respect to parameters such as the ionic nature of the electrolyte. Polypyrrole obtained in the presence of dodecyl sulphate shows a higher stability and electroactivity in comparison with polypyrrole doped with inorganic dopants.

Properties of electrochemically synthesized polymer electrodes—X. Study of polypyrrole/dodecylbenzene sulfonate

Abstract The electrochemical behavior of polypyrrole films electrosynthesized in the presence of dodecylbenzenesulfonate has been investigated by cyclic voltammetry and frequency response analysis. The results indicate that the kinetics of the redox process are mainly governed by diffusion of the cations and anions of the supporting electrolyte while the large surfactant anions remain immobilized in the polymer structure.

A new electrode for a poly(pyrrole)-based rechargeable battery

The use of dodecylbenzenesulfonate-doped poly(pyrrole) films, PPYDBS, as a secondary battery electrode was studied. The redox and morphologic properties of these films are suitable for battery application. Films were synthesized by electrolysis of pyrrole and sodium dodecylbenzenesulfonate aqueous solutions with a current density of 1.0 mA cm−2 and were switched in LiC1O4 1.0 M propylene carbonate solutions (PC) by cyclic voltammetry. In these experiments an apparent diffusion coefficient of 3.7x10−9 cm2s−1 has been found. Charge/discharge tests at ±50, ±100, ±150 and ±200 μA cm−2 were done for a PPYDBS/ LiC1O4, PC/Li battery. The open-circuit voltage was 3.2 V after 30 h, the specific capacity 53 A h kg−1 and the energy density 154 W h kg−1. These values indicate that this polymer can be used as an electrode in a rechargeable battery.

Properties of poly(pyrrole) films electrochemically synthesized in the presence of surfactants

Abstract Flexible poly(pyrrole) films with conductivities in the range of 15 S/cm were obtained by the galvanostatic polymerization of pyrrole in an aqueous electrolyte using sodium dodecylsulphate as anionic counter-ion. The effect of the current density on the final properties of the films was studied with constant surfactant concentration. The films have been characterized by Fourrier-transform infrared spectrophotometry, scanning electron microscopy, elemental analysis and four-point probe conductivity measurements.

Electrochromic properties of dodecyclbenzenesulfonate doped poly(pyrrole)

Abstract The galvanostatic synthesis of dodecylbenzenesulfonate doped poly(pyrrole), PPYDBS, on ITO electrodes produces homogeneous films which show a color change from yellow to dark blue when cycled in aqueous KCl between −0.75 and 1.00 V (vs. sce ). During the continuous switching by cyclic voltammetry the color change is accompanied by a hysteresis effect which is assigned to relaxation processes of the pyrrole rings. The synthesis conditions, electrolyte and film thickness play an important role in this behavior. The electrochromic stability tests show that these films are stable to 3.5 × 10 3 potential redox steps from −0.6 to 0.4 V.

Electrochromic properties of poly(pyrrole)/dodecylbenzenesulfonate

We present the electrochromic properties of dodecylbenzenesulfonate-doped poly(pyrrole). The galvanostatic synthesis on ITO electrodes produces homogeneous films which show a transmittance change from 80% to 40% at 700 nm when cycled in aqueous KC1 between -0.75 and 1.00 V (SCE). These films are stable to 3.5 X 103 potential redox steps from -0.6 to 0.4 V (SCE).