The dependence of the nanostructure of porous anodic alumina films (PAAFs) on anodizing potential is useful in studies of PAAF growth kinetics and mechanism and for adjusting their structural properties for numerous applications often through linear dependencies that are not sufficiently justified. Suitable Al anodizing experiments were performed. Proper equations were formulated describing in steady state the dependence on the anodic potential Pan and the electrolysis voltage ΔV of PAAFs’ main structural features, mean cell width Dc, pore base diameter Dp and barrier layer thickness blt. In the widest Pan and ΔV definition domains, retaining typical PAAF structure, these are implicit pseudo-linear equations, Dc = fcPan = fcΔV + gc, Dp = fpPan = fpΔV + gp and blt = fbPan = fbΔV + gb, (fc, fp, fb > 0), (gc, gp, gb < 0), where fc, fp, fb, gc, gp and gb generally depend on many kinetic parameters, some of which depend in turn on Pan, ΔV or other additional parameters, some of which are interdependent etc. These equations describing the dependence of Dc, Dp and blt on Pan and ΔV become exact linear in anodizing regimes ensuring that all kinetic parameters defining fc, fp, fb gc, gp and gb are constant, which is rather impossible within such domains. If fc, fp, fb, gc, gp and gb change, the Dc, Dp and blt vs. Pan and ΔV plots deviate from linear by different modes, while each plot profile may differ from the rest. Experimental linear approximations refer to narrower domains, often for anodizing regimes giving the best hexagonal order of pores. The shift of domains produces changes in gradient and intercept. Moreover the intercept may become < 0 or ≥ 0. Linear or other monotonic Dc, Dp and blt vs. Pan or ΔV plots and exceptions are sufficiently explained for the first time. These results are important for Al anodizing electrochemistry and PAAF applications.
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