间甲基苯胺电化学聚合以及它与对苯二胺电化学共聚的原位紫外-可见光谱

In situ UV-Vis Spectroelectrochemistry for Electropolymerization of m-Toluidine and Electrocopolymerization of m-Toluidine with p-Phenylenediamine

在0.5mol·dm-3硫酸介质中,循环伏安法电解间甲苯胺的原位紫外可见光谱图表明聚间甲基苯胺产生在氧化铟锡导电玻璃电极表面上.在恒电位条件下,用原位紫外-可见光谱较详细地研究了间甲基苯胺在氧化铟锡(ITO)上的电化学聚合.结果表明间甲基苯胺只能在较高电解电位和单体浓度足够大的条件下才能发生电化学聚合.在0.7V(相对于饱和的Ag/AgCl),0.2mol·dm-3的间甲基苯胺和0.9V,20mmol·dm-3的间甲基苯的实验条件下,尽管在ITO电极上没有发生电化学均聚合,但原位紫外-可见光谱表明在电极表面上可能还形成低分子量的齐聚物.在低电位0.8V下,电化学聚合200mmol·dm-3间甲苯胺时,有明显的诱导期存在.在恒电位电解的条件下,相应的原位紫外-可见光谱和聚合物的傅立叶变换红外光谱(FTIR)表明间甲基苯胺和对苯二胺能发生电化学共聚反应,由于对苯二胺可能与间甲基苯胺形成了具有较强反应活性的中间体,使得对苯二胺的加入不但促进和加速了聚合反应,而且还结合进聚合物中形成了phenazine或类似于phenazine的环结构.

In a 0.5 molodm^-3 sulfuric acid medium, cyclic voltammograms of m-toluidine and its corresponding in situ UV-Vis spectra indicate that the poly（m-toluidine） film was produced on the surface of the electrode. Under the condition of potentiostatic electrolysis, the electropolymerization of m-toluidine on an indium-tin oxide （ITO） conductive glass electrode was studied in detail by in situ UV-Vis spectrometry. It was showed that m-toluidine could be electropolymerized on the ITO electrode only under the condition of higher electrolysis potential and lager concentration of the monomer. At 0.2 molodm^-3 of m-toluidine, 0.7 V （vs. saturated Ag/AgCl） and 20 mmol·dm^-3 of m-toluidine, 0.9 V （vs. saturated Ag/AgCl）, in situ UV-Vis spectrometry indicated that the polymerization did not happen whereas the low molecule weight oligomer such as dimers could be produced on the ITO electrode. The obvious induction period was observed when elctropolymerization of m-toluidine was performed in the 200 mmol·dm^-3 m-toluidine at 0.8 V （vs. saturated Ag/AgCl）. Furthermore, in situ UV-Vis spectra showed that the electrocopolymerization between m-toluidine and p-phenylenediamine was performed. The p-phenylenediamine might react with m-toluidine to yield more active intermediates, which not only promote polymerization but also accelerate polymerization. In addition, through that p-phenylenediamine could be incorporated into copolymer to make the copolymer have a phenazine or phenazine like cyclic structure, which was proved by the FTIR of polymers.