Ia. Arkoub et al., Diffusion at double microband electrodes operated within a thin film coating. Theory and experimental illustration, J PHYS CH B, 105(37), 2001, pp. 8694-8703
The diffusion transport of reversible redox species was investigated at mic
robands in a thin film coating. The effect of the film thickness onto the d
iffusion was studied theoretically and by numerical simulations both at sin
gle-band and double-band microelectrodes. According to the diffusion length
of the species in this restricted volume, the corresponding theory and sim
ulations show that several diffusional regimes are expected which provide a
way to estimate both the diffusion coefficient and concentration of the sp
ecies but also to evaluate at the same time the film thickness. This has be
en demonstrated experimentally by examining the electrochemical responses o
f microbands coated by Fe-III-loaded Nafion films of different thicknesses.
A very good agreement is obtained between theory and experiments which sho
ws that the electrochemical responses of such devices afford a possibility
of monitoring the physical and geometrical properties of a polymer film in
relation to its chemical environment.