Surface changes of electrochemically-grown polypyrrole films on vitreous carbon substrates areanalyzed by atomic force microscopy (AFM) as a function of the pH of the source solutions. Thickfilms are obtained when using H2SO4 (i.e., 8.035 m thick when grown at constant potential, CP and0.157 m thick when grown by cyclic voltammetry, CV). Such values are estimated from thecorresponding areas under the curves either for the i vs. t (CP) or for the i vs. V (CV) plots. PPy filmsgrown at constant potential are thicker than those formed by cyclic voltammetry. In general, filmthickness follows essentially the same pattern regardless of the growth technique as a function of pH2- 2- - - and of the nature of the anion as follows: SO4 (pH = 1) > SO4 (pH = 7), Cl (pH = 1) > Cl (pH = 7).The electrosynthesis potential plays a key role in the final film characteristics, since overoxidation isobserved at high applied potentials and promotes considerable stability and conductivity losses.
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机译：通过原子力显微镜（AFM）分析玻璃碳基材上电化学生长的聚吡咯膜的表面变化，作为源溶液pH的函数。使用H2SO4可获得厚膜（即在恒定电势下生长时为8.035 m厚，CP和通过循环伏安法在CV下生长时为0.157 m厚）。对于i vs. t（CP）或i vs. V（CV）图，可从曲线下的相应区域估计这些值。在恒定电位下生长的PPy膜比通过循环伏安法形成的PPy膜厚。通常，膜厚遵循基本相同的模式，而与增长技术无关，取决于pH2- 2--和阴离子的性质，如下所示：SO4（pH = 1）> SO4（pH = 7），Cl（ pH = 1）> Cl（pH = 7）。电合成电位在最终的薄膜特性中起关键作用，因为在高施加电位下会观察到过氧化作用，并会导致相当大的稳定性和电导率损失。
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