In situ electrochemical and surface plasmon resonance (SPR) studies of aniline-carboxylated aniline copolymers
In situ electrochemical and surface plasmon resonance (SPR) studies of aniline-carboxylated aniline copolymers
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DOI：
10.1016/j.aca.2005.11.006
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发表时间：
2006-02
影响因子：
6.2
通讯作者：
Yanju Wang;W. Knoll
中科院分区：
文献类型：
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作者：
Yanju Wang;W. Knoll
采用循环伏安法，在酸性水溶液中，通过苯胺和羧基化苯胺的电化学共聚反应制备了自掺杂导电聚苯胺（PAn）。羧基取代和未取代聚苯胺的对比研究表明，只有苯胺（An）和2-邻氨基苯甲酸（AA）的共聚物在中性水溶液中具有较高的电活性和电极稳定性。通过原位电化学和表面等离子体共振光谱（SPR）研究了共聚物的聚合过程、氧化还原性质和稳定性，并与金电极上的聚合物进行了比较。在SPR监测的聚合过程中，取代和未取代的聚苯胺分别观察到了“自抑制效应”和“自催化效应”。电化学和表面等离子体共振技术的结合提供了有关聚合物在氧化还原过程中介电性能和膜厚变化的直接信息。与聚苯胺和共聚物相比，取代聚苯胺的介电常数在不同氧化还原态之间变化时对SPR反射率的影响较小。在酸性环境中从苯胺及其取代的类似物获得的这些共聚物的可比电活性表明存在类似的共轭结构的共聚物和聚苯胺，这是进一步证实了全内反射FTIR（TIR-IR）。
Self-doped conducting polyanilines (PAn) were fabricated by electrochemical copolymerization of aniline and carboxylated anilines in acidic aqueous solution using cyclic voltammetry. The comparative studies of carboxyl substituted and unsubstituted polyanilines show that only the copolymers from aniline (An) and 2-anthranilic acid (AA) with appropriate monomer fractions retain a high electroactivity and stability on electrodes in neutral aqueous solution. The polymerization process, the redox properties and the stability of the copolymers in comparison with those of polymers on gold electrodes were thoroughly investigated by in situ electrochemistry and surface plasmon resonance spectroscopy (SPR). The “self-inhibiting effect” and the “autocatalytic effect” were observed in the substituted and the unsubstituted polyanilines separately during the polymerization processes monitored by SPR. The combination of electrochemical and SPR techniques provides the direct information about the changes of dielectric properties and film thickness of the polymers in their redox processes. Comparing with those of PAn and copolymers, the dielectric constants of the substituted polyaniline play a minor role in the SPR reflectivity when it changes between different redox states. The comparable electroactivity of these copolymers obtained from aniline and its substituted analogues in acidic environments indicates the presence of a similar conjugated structure of the copolymer and the polyaniline, which is further confirmed by total internal reflection FTIR (TIR-IR).