In situ UV–vis spectroelectrochemistry of poly(o-phenylenediamine-co-m-toluidine)

Investigation of the electropolymerization of o‐toluidine and p‐phenylenediamine and their electrocopolymerization by in situ ultraviolet–visible spectroelectrochemistry

“…However, after a longer electrolysis time, more cation radicals and some oxidation state oligomer gathering near or on the electrodes cause the polymerization reaction on the electrode to proceed more quickly, which is one of the reasons that the polymerization of aniline and its derivatives is autocatalysis reaction, as mentioned by some reports. 30,[37][38][39] These conclusions also were supported by the in situ spectra shown in Figure 1 14 This showed that no sufficient amount of cation radicals was produced because of the lower OT concentration in solution so that POT did not grow, but the lower molecular weight oligomers of OT, such as dimers, trimers, and tetramers, should have been produced. This was in agreement with our study on the electropolymerization of aniline.…”

“…After the start of electrolysis, two bands around 320 and 700 nm were obvious, which indicated that the poly(o-toluidine) (POT) was formed on the ITO electrodes. The bands around 320 and 700 nm were assigned to the p-p* transition 30,31 of the benzoic ring and to the polaronic transition 30,[32][33][34] in POT, respectively. In comparison, the intensities of the absorption bands for 0.2M OT at potentials of 0.9 and 0.8 V increased faster than at a potential of 0.7 V. In addition, the plots of the absorbance at 700 nm in Figure 1(a-c) versus the electrolysis time shown in Figure 2 show that the absorbance of 700 nm at a potential of 0.7 V began to increase evidently 10 min after constant electrolysis was started, which indicated that there was an induction period in the electropolymerization of OT similar to the chemical and electrochemical polymerization of aniline and its other derivatives.…”

<i>In Situ</i> UV–Vis Spectroelectrochemical Studies on the Copolymerization of Diphenylamine and <i>o</i>-Phenylenediamine

“…However, with the time increasing, another weak absotption peak at 550 nm can be observed. It has been reported that there are three absorptive bands located at 420 nm, 462 nm and 492 nm, respectively, in its UV-Vis spectrum [30]. This difference may be resulted from the different medium used.…”

“…The obtained homo-/co-polymers had been characterized using CV and in situ conductivity measurements, and it was found that the copolymers showed an extended electrode potential range of redox activity and good redox responses at higher pH-values in comparison with the homopolymers of POPD, poly(o-toluidine) (POT) and poly (m-toluidine) (PMT) as well as good electrochemical stability. Also, Holze et al [30] have studied the initial stages of the copolymerization of OPD with MT, monitored with in situ UV-vis spectroscopy, using an ITO-coated glass electrode in solutions with a constant concentration of MT and varying OPD concentrations. The formation of aniline type mixed intermediates as a result of the cross-reaction between the cation radicals of OPD and MT was proposed from the presence of the band at 497 nm during the electro-polymerization of OPD and MT.…”

Comparative Study on Electrocopolymerization ofm-Toluidine ando-Toluidine

“…合物中相邻苯环中的 π-π*电子跃迁产生的 [11,12] ; 后者是 半氧化态聚苯胺类导电聚合物骨架中极化子跃迁引起 的 [11,13～15] . 这些均说明在此条件下间甲基苯胺发生了电 化学聚合反应.…”