Redox Reactions of Polyaniline-Coated Latex Suspensions

Abstract

Electrically conducting redox-active particles were synthesized by coating near-monodisperse, micrometer-sized polystyrene latex particles (1.62 μm diameter) with polyaniline at 0 °C. This low-temperature synthesis route ensured that high-quality polyaniline was produced. The purified particles were dispersed in an aqueous acidic surfactant solution. According to bulk electrolysis measurements, the reduction of each latex particle leads to the transfer of n = 1.7 × 109 electrons. The acidic suspension showed a cathodic peak at 0.10 V and a very small anodic peak at 0.20 V. The former feature corresponds to the reduction wave, i.e., the conversion of polyaniline from its electrically conducting emeraldine form to its insulating leucoemeraldine state. The cathodic wave varied from a surface wave at lower latex concentration to a diffusion wave at higher latex concentration. The peak current varied linearly with the square root of the potential scan rate, giving a value of n similar to that obtained from bulk electrolysis. The irreversibility of the voltammogram, i.e., the disappearance of the anodic wave, was ascribed to such a short time of collision with the electrode that the conducting zone can propagate only to a small domain near the collision point.

Poly(taurine)/MWNT-modified glassy carbon electrodes for the detection of acetaminophen

“…A shiny and light green color was found on the electrode surface after eight cycles. Similar colorful films have been also reported due to the formation of polymers [43][44][45]. These results indicate the fabrication of poly(taurine) layers on MWNT-film coated electrode.…”

Is Voltammetric Current Proportional to the Number of Transferred Electrons for Multi‐Charged Ions or to 3/2 Power of the Number?

“…The invariance of the linear sweep waveform with n has been demonstrated experimentally for silver nanoparticles [14 -16] redox latexes [26 -34] and redox polymers [35 -37]. The number of n has been already determined from the equation similar to Equation 20, which had been obtained intuitively [31]. The values of n were consistent with values estimated from bulk electrolysis [27 -31], spectroscopy [34], thermal analysis [15] and chemical analysis [14].…”

“…However, it becomes a new subject when the attention is paid to large particles with multiple charge transfer such as dendrimers [12 -13], nanoparticles of metal [14 -20], redox polyelectrolytes [21 -25], redox latex particles [26 -34] and redox polymers [35 -37]. Since the voltammetric currents play an important role in determining the structure of large particles through n [31,33,34] it is necessary to discuss in detail the relation between the peak current and n. In this paper we derive expressions for voltammetric currents at any timepotential sequence under the diffusion-control of a large particle with n transferring electrons on the assumption of the Nernst equation for n-time consecutive one-electron reactions.…”

Size-dependent electrocatalytic reduction of nitrite at nanostructured films of hollow polyaniline spheres and polyaniline–polystyrene core–shells

“…Tel. : +353 1 700 7871; fax: +353 1 700 7873. of stability in suspension [11], adsorption properties [12], aggregation [13], and glass transition temperatures [14] in a broad range of sizes have been extensively reported in the literature [12][13][14][15][16]. Bartlett et al.…”