Research Article

Electrochromism and Swelling of Polypyrrole Membranes: An Electrochemical and Ellipsometric Study

Figure 3

(•) Evolution of the experimental parameters and after successive cycles in the condition of Figure 1, namely, (a) Ea = 1.2 V and = 20 s, (b) Ea = 1.4 V and = 15 s. The figures correspond to number of cycles. Evolution of the thicker film changing the potentials in both (□): SDS and (): after immersion in KCl. (○): Theoretical values corresponding to a layer of optical index n and increasing the thickness, d, every 8 nm. The film obtained at Ea = 1.2 V fits n = 1.343 − i0.101 and that obtained at Ea = 1.4 V fits n = 1.3476 − i0.0723. Owing of the change in the plot scale, both fitted curves are plotted in (b) for comparison.