ION-TRANSPORT IN POLYPYRROLE AND A POLYPYRROLE POLYANION COMPOSITE
ION-TRANSPORT IN POLYPYRROLE AND A POLYPYRROLE POLYANION COMPOSITE
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DOI：
10.1021/j100122a029
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发表时间：
1993-05-20
影响因子：
--
通讯作者：
PICKUP, PG
中科院分区：
文献类型：
--
作者：
REN, XM;PICKUP, PG
在0.2 M氯化钠（aq）溶液中，用阻抗谱法测定了聚吡啶聚苯乙烯磺酸盐（PPY/PSS）和聚吡啶高氯酸盐（PPY/ClO4-）薄膜在电极上的离子电导率与氧化水平的关系。随着氧化水平的增加，PPY/ClO4-的离子电导率增加，而PPY/PSS的离子电导率降低。结果表明，阴离子传输主要影响PPY/ClO4-的离子电导率，而阳离子传输主要影响PPY/PSS的离子电导率。这种离子传输模式的差异在循环伏安法中通过峰电位扫描速率依赖性的差异反映出来。在这两种情况下，与移动离子插入膜相对应的伏安峰值对增加扫描速率最敏感。在所有电位下，PPY/PSS的离子电导率均显著高于PPY/ClO4-，表明PPY/PSS中的Na+比PPY/ClO4-中的ClO4-更具移动性。ClO4-的低迁移率归因于与氧化聚吡咯位点的离子配对。PPY/PSS在含有甲基紫素的溶液中的阻抗行为为这一解释提供了证据。甲基紫蛋白指示物被膜中的磺酸基固定，并在电位循环过程中抑制阳离子运输。因此，聚合物的氧化涉及到ClO4-的吸收，其离子电导率的电位依赖性和大小成为PPY/ClO4-的特征。
The ionic conductivities of polypyrrole poly(styrenesulfonate) (PPY/PSS) and polypyrrole perchlorate (PPY/ClO4-) films on electrodes have been measured in 0.2 M NaClO4(aq) as a function of oxidation level by impedance, spectroscopy. As the oxidation level is increased, the ionic conductivity of PPY/ClO4- increases, while that of PPY/PSS decreases. It is concluded that anion transport is primarily responsible for the ionic conductivity of PPY/ClO4-, while cation transport dominates in PPY/PSS. This difference in the mode of ion transport is reflected in cyclic voltammetry by differences in the scan rate dependence of peak potentials. In both cases, the voltammetric peak corresponding to insertion of the mobile ion into the films is most sensitive to increasing scan rate. The ionic conductivity of PPY/PSS is significantly higher than that of PPY/ClO4- at all potentials, indicating that Na+ in PPY/PSS is more mobile than ClO4- in PPY/ClO4-. The low mobility of ClO4- is attributed to ion pairing with oxidized polypyrrole sites. Evidence for this interpretation is provided by the impedance behavior of PPY/PSS in solutions containing methylviologen. The methylviologen dications become immobilized by the sulfonate groups in the film and inhibit cation transport during potential cycling. Oxidation of the polymer therefore involves ClO4- uptake and the potential dependence and magnitude of its ionic conductivity become characteristic of PPY/ClO4-.