**1. Introduction**

96 Electropolymerization

Zhou H.; Wen J.; Ning X.; Fu C.; Chen J. & Kuang Y. (2007). Electrosynthesis of polyaniline

Zhou S.; Wu T.; Kan J. Effect of methanol on morphology of polyaniline.(2007). *European Polymer Journal*, Vol. 43, No. 2, (February 2007), pp. 395-402, ISSN0014-3057 Zotti G; Cattarin S. & Comiss N. (1987). Electrodeposition of polythiophene, polypyrrole

Zotti G; Cattarin S. & Comiss N. (1988). Cyclic potential sweep electropolymerization of

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films on titanium by pulse potentiostatic method. *Synthetic Metals*, Vol. 157, No. 2-3,

and polyaniline by the cyclic potential sweep method. *Journal of Electroanalytical Chemistry and Interfacial Electrochemistry*, Vol. 235, No. 1-2, (October 1987), pp. 259-

aniline: The role of anions in the polymerization mechanism. *Journal of Electroanalytical Chemistry and Interfacial Electrochemistry*, Vol. 239, No. 1-2, (January

> Polyanilines contain anioniogenic functional groups are denominated self-doped polyanilines. These polymers possess properties different from those of polyaniline (PANI) as suppressed or no need on anion doping during oxidation or reduction processes, solubility in aqueous base, extended redox activity for neutral and basic solution, making them promising applications such as biosensors as a result of physiological pH values, and rechargeable batteries due to the fact that self doping polyanilines are capable of storing more specific energy than PANI as a function of self-doping (Malinauskas, 2004). Therefore it is important the development of these types of polymers, the electrochemical oxidation of 5-amino-2-naphtalensulfonic (ANS) and the luminol can be done a self-doped homopolymer, however the electropolymerizaton of these compounds has not been studied. The chemical structures of these monomers are similar in three aspects (Figure 1): (a) both ANS and luminol contain into their chemical structure the aniline; (b) It is difficult obtain a film of homopolymers to these monomers, because the electroxidation in milium acid of luminol produce a dimmer (De Robertis et al., 2008; Ferreira et al., 2008) in fact the solubility of luminol is bass in this milieu, in these conditions is favored the formation of dimmers; on the other hand no deposition of a polymer onto the electrode has been observed when others amino naphtalensulfonic acid has been electrochemically oxidate, probably for the reason that oligomers are very soluble (Mažeikienė & Malinauskas, 2004). (c) A self-doped polymer can be obtained by copolymerization with aniline and whoever of these monomers (De Robertis et al., 2008; Ferreira et al., 2008, Mažeikienė & Malinauskas, 2004).

> So large of our knowledge there are no reports of the homopolymerization of ANS and luminol, the importance of the synthesis of each films consist in the case of ANS in obtain information of the effect of the separation of group sulfonic to aniline in the ion exchange of film, because the charge compensation has been evaluated principally for ring substituted

Electrochemical Preparation and Properties of Novel Conducting Polymers

**2.3 Electrochemical measurements** 

+ 0.5 M aniline.

continuation.

**3. Results and discussion** 

**3.1 Electrosynthesis and characterization of polyANS**

Derived from 5-Amino-2naphtalensulfonic Acid, Luminol and from Mixtures of Them 99

Fig. 2. Photograph of A) diassembled and B) assembled cell: (a) acrylic sample container, (b) acrylic cell cover, (c) teflon quartz crystal and his container, (d) O-rings, (e) acrylic cover of quartz cristal container, (f) teflon cover of quartz crista container and (g) coin (φ = 0.8 cm).

Electrochemical experiments were carried out in a three–compartment cell in a high purity nitrogen atmosphere at room temperature. The electrode reference consisting of Ag⏐AgCl⏐3 moldm-3 NaCl (BAS) and the counter electrode was a platinum wire. The working electrodes were: carbon paste electrode (0.1452 cm2), glassy carbon, Au and Pt (0.0707 cm2) and a 9 MHz AT-cut quartz crystal coated with gold (0.1963 cm2). Two types of carbon paste electrode were prepared the first by intimately mixing 1.0 g of finely ground graphite powder with 1.0 g of Nujol. The second type of electrode is characterized by included the monomer into the carbon paste bulk, the electrode is prepared mixing graphite powder, nujol and the monomer. In both cases the resulting paste was then packed into a plastic 1 mL syringe in which a piece of coop wire was wound to produce the electrical contact. The surface was smoothed by a weight paper before each experience. The glassy carbon, Au and Pt electrodes were systematically polished successively with 3 and 1 μm polish diamond (BAS) on a Microcloth felt disk (BAS). Following this, the electrodes were thoroughly rinsed with deionised water and sonicated in an ultrasonic bath for 10 minutes. The precoated PANI film for electrodeposition of polyANS was carried out by realizing 10 cycles of potential between -200 and 1200 mV, except for the three first cycles for which the upper limit was 1100 mV. The scan rate was 50 mVs-1, and the electrolyte solution was 0.5 M H2SO4

The electrosynthesis of a film of polyANS was tested by chronopotenciometry and cyclic voltametry in five different electrodes: Au, Pt, glassy carbon, carbon paste and Au modified with PANI. No deposition of a polymer onto the Au, Pt and glassy carbon electrodes was observed, in agreement to reported for aminonaphtalen disulfonics acids (Mažeikienė & Malinauskas, 2004) probably because the products formed during the oxidation are very solubles. On the contrary film growth was presented onto carbon paste and Au/PANI electrodes, the syntheses and properties obtained in each electrode are presented to

anilines (Barbero et al., 1994; Cano-Márquez et al., 2007; Mello et al.,2000; Varela et al.; 2001). In the case of homopolymer of luminol should be studied as influence the chemical nature of film in the proprieties obtain and in the activity electrocatalitic; in fact these proprieties are only reported for the dimmer of luminol (Chen & Lin, 2002). On other hand as the polymer obtained to luminol not is water soluble, in consequence the copolymerization of these two monomers can be result of a deposition a self doping polymer film. The goal of this study is the electrosynthes of three novel conducting polymers: polyANS, polyluminol (only has been reported dimmers of luminol) and copolymer, obtained to ANS, luminol and both respectivally, the evaluation of proprieties of films obtained as well as: activity electrocatalytic to ascorbic acid, electrochemical activity in pH neutral and study the charge compensation using the electrochemical quartz crystal microbalance (EQCM) during the redox process only for polyANS.

Fig. 1. Chemical structure of momomers used in the present study.
