Cyclic voltammetry poly aniline

Cyclic voltammetry is also an ideal analytical tool for assessing the electrochemical stability of the polymer films. This is a fundamental requirement for any conducting polymer to be considered for long-term use in electrochemical devices. The use of ionic liquids for the electrochemical cycling of poly(aniline) has been reported to enhance lifetimes to over a million cycles [12], and significant improvements in the cycling stability of poly(pyrrole) have also been reported [32]. 

Fig. 2.19. (A) The effect of potential on the observed electrocatalytic response obtained at poly(aniline)/poly(vjnylsu fonate) electrode (geometric area 0.38 cm2, Q, 150 mC) rotated at 9 Hz in 0.1 mol dm-2 citrate/phosphate pH 7 buffer solution. Responses have been recorded at four different concentrations of NADH ( ) 0.12 mmol dm- ( ) 0.3 mmol dm"3 ( ) 0.6 mmol dm-3 and (O) 0.8 mmol dm"3. (B) Cyclic voltammetry of an identical poly(aniline)/poly(vinylsulfonate) electrode in 0.1 mol dm" 3 citrate/phosphate pH 7 buffer scanned at 5mVs , superimposed on this trace is the measured resistance for the same...

Electrochemical homopolymerization of poly(aniline-N-alkylsulfonates) (alkyl = propyl, butyl and pentyl) in acetonitrile containing 0.1 M NaC104 and 5 % (v/v) 0.3 M HCIO4 was carried out by Rhee et al. [144]. The polymers were prepared on a platinum electrode by cyclic voltammetry (0.0 to 1.0 V vs Ag/AgCl) or potentiostatic techniques (1.0 V). These polymers were found to form liquid crystalline solutions in water. The conductivity of poly(aniline-N-propanesulfonic acid) and poly(aniline-N-butanesulfonic acid) was reportly 9 x 10 and 6 x 10 S/cm, respectively. Electrochemical polymerization of orthanilic acid, metanilic acid and sulfonic acid and their copolymerization with aniline in dimethyl sulfoxide containing tetrabutyl ammonium perchlorate were carried out by Sahin et al. [145]. These polymers and copolymers were found to be soluble in water, dimethyl sulfoxide and N-methylpyrrolidinone. The conductivity of orthanilic acid, metanilic acid and sulfonic acid was reportly 0.052,0.087 and 0.009 S/cm, respectively. The conductivity of copolymers for these three isomers of aminobenzene-sulfonic acid was reported as 0.094, 0.26 and 0.033 S/cm, respectively. Sahin et al. [146] have also prepared the copolymers of these three isomers with aniline in acetonitrile containing fluorosulfonic acid (FSO3H). The copolymers were found to be soluble in water, dimethyl sulfoxide and N-methylpyrrolidinone. 

FIGURE 1.39. Composite cyclic voltammetry (A)/quartz crystal microbalance (B) data for electrodeposited poly(aniline) films in IM H2SO4 supporting electrolyte. Sweep rate 100 mV s current sensitivity C = 100/liA, F - 20 Hz. Note that curve B is offset 40 mV to the left with respect to curve A (see Ref. 133). 

Figure 20.47. Cyclic voltammetry of a sodium poly(aniline propanesulfonate) film in LiCIOVacetonitrile. (Reprinted by permission of ref 38)...

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