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Controlled Completion of Oxidation

When a polymer relaxes at a constant anodic potential, the relaxation and partial opening of the polymeric structure involve a partial oxidation of the polymer. Once relaxed, the oxidation and swelling of the relaxed polymer goes on until total oxidation is reached this is controlled by the diffusion of the counter-ions through the film from the solution. This hypothesis seems to be confirmed by the current decay after the chronoam-perometric maximum is reached. We will focus now on the diffusion control. [Pg.389]

The concentration of the remaining oxidation centered on the relaxed film at any oxidation time is defined by the difference between the density of charge stored in the point at which the film attains an oxidation steady state at the working potential and large polarization times and the charge density stored after a given polarization time [ j(0]-So the diffusion flow of ions is given by [Pg.389]

An infinitesimal fraction of the polymer will be considered, consisting of all the segments that are relaxed at the same time (f). As result of the flow given by Eq. (32), the increment of charge stored under diffusion control [dQd(t) in this infinitesimal portion of the polymer at a given time t f, will be given by [Pg.390]

dQd is the overall diffusion charge for the segments relaxed at a time f. Its value can be related to the infinitesimal increment in the area of the conducting regions between f and f + dt, according to Eq.(31)  [Pg.390]

The integration of Eq. (36) yields the diffusion charge consumed until a given time in those regions where the structure was opened  [Pg.390]


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