阴离子种类对苯胺电聚合过程的影响

Effects of Different Anions on Aniline Electropolymerization

聚苯胺材料的结构及性质与电化学聚合条件之间具有密切的联系,在苯胺的电聚合过程中,不同的阴离子对聚苯胺薄膜的形核过程、形成速率等产生不同程度的影响。采用循环伏安及交流阻抗等电化学测试方法,在含有NO_3^-,SO_4^(2-),Cl^-,ClO_4^-及PO_4^(3-)等不同种类阴离子的酸性溶液中,对苯胺在金电极表面的电聚合过程进行了研究,并采用等效电路图对聚合原理进行进一步的分析。结果表明:苯胺单体氧化为自由基是苯胺电聚合过程中的关键步骤,苯胺在含有不同种类阴离子溶液中氧化为阳离子自由基的难易程度顺序为NO_3^->SO_4^(2-)>ClO_4^->Cl^->PO_4^(3-),其中苯胺在掺杂PO_4^(3-)的溶液中具有最低的反应电阻,这与PO_4^(3-)显著的催化作用有关。

It is reported that the struclures and properties of polyaniline materials have close connection with polymerization conditions.During the process of aniline electropolymerization,different anions have varying degree of influences on the nucleation and the formation rate of polyaniline films.The aniline electropolymerization process was studied by cyclic voltammograms(CV) and electrochemical impedance spectrometry(EIS) on the All electrode in different acid solutions doped with anions such as NO^-3^-,SO_4^(2-),Cl^-,ClO_4 and PO_4^(3-).Subsequently,the principles of polymerization were further analyzed by using the proposed electrical equivalent circuits.Results showed that the key step for aniline electrodeposition was the oxidation of monomer aniline to its cation radicals,and the order from difficulty to easiness of the anions dissolved in different electrolytes for aniline oxidation to cation radical was NO_3^->SO_4~2-)>ClO_4^->Cl^-> PO_4^(3-).Particularly,the reaction had the lowest resistance in the solution contained PO_4^(3-),due to the notable catalytic effect of PO_4^(3-).