二茂铁键合聚氯乙烯作为电化学离子传感器中的离子到电子转换器。

Nanochemistry Research Institute, Department of Chemistry, Curtin University of Technology, Perth, Western Australia 6845, Australia.

Anal Chem. 2010 Aug 15;82(16):6887-94. doi: 10.1021/ac1010662.

We report here on the synthesis of poly(vinyl chloride) (PVC) covalently modified with ferrocene groups (FcPVC) and the electrochemical behavior of the resulting polymeric membranes in view of designing all solid state voltammetric ion sensors. The Huisgen cycloaddition ("click chemistry") was found to be a simple and efficient method for ferrocene attachment. A degree of PVC modification with ferrocene groups between 1.9 and 6.1 mol % was achieved. The chemical modification of the PVC backbone does not significantly affect the ion-selective properties (selectivity, mobility, and solvent casting ability) of potentiometric sensing membranes applying this polymer. Importantly, the presence of such ferrocene groups may eliminate the need for an additional redox-active layer between the membrane and the inner electric contact in all solid state sensor designs. Electrochemical doping of this system was studied in a symmetrical sandwich configuration: glassy carbon electrode |FcPVC| glassy carbon electrode. Prior electrochemical doping from aqueous solution, resulting in a partial oxidation of the ferrocene groups, was confirmed to be necessary for the sandwich configuration to pass current effectively. The results suggest that only approximately 2.3 mol % of the ferrocene groups are electrochemically accessible, likely due to surface confined electrochemical behavior in the polymer. Indeed, cyclic voltammetry of aqueous hexacyanoferrate (III) remains featureless at cathodic potentials (down to -0.5 V). This indicates that the modified membrane is not responsive to redox-active species in the sample solution, making it possible to apply this polymer as a traditional, single membrane. Yet, the redox capacity of the electrode modified with this type of membrane was more than 520 microC considering a 20 mm(2) active electrode area, which appears to be sufficient for numerous practical ion voltammetric applications. The electrode was observed to operate reproducibly, with 1% standard deviation, when applying pulsed amperometric techniques.

我们在此报告了通过 Huisgen 环加成（“点击化学”）将二茂铁基团共价键合到聚氯乙烯（PVC）上的合成方法，以及由此产生的聚合物膜在设计全固态伏安离子传感器方面的电化学行为。发现 Huisgen 环加成（“点击化学”）是一种将二茂铁基团连接到 PVC 上的简单而有效的方法。可以实现 1.9 到 6.1 摩尔％的 PVC 与二茂铁基团的化学修饰程度。化学修饰 PVC 主链不会显著影响应用该聚合物的电位传感膜的离子选择性（选择性、迁移率和溶剂浇铸能力）。重要的是，在全固态传感器设计中，在膜和内部电接触之间可能不需要添加额外的氧化还原活性层。该系统的电化学掺杂在对称三明治结构中进行：玻碳电极| FcPVC|玻碳电极。通过在水溶液中进行电化学掺杂来证实之前的电化学掺杂，这会导致二茂铁基团部分氧化，这对于三明治结构有效地传递电流是必要的。结果表明，只有大约 2.3 摩尔％的二茂铁基团是可电化学获得的，这可能是由于聚合物中的表面受限电化学行为。事实上，在负向电位（低至-0.5 V）下，六氰合铁（III）的循环伏安法仍然没有特征。这表明修饰后的膜对样品溶液中的氧化还原活性物质没有响应，从而可以将该聚合物用作传统的单膜。然而，考虑到 20 mm(2) 的有效电极面积，这种类型的膜修饰的电极的氧化还原容量超过 520 微库仑，这似乎足以满足许多实际的离子伏安应用。当应用脉冲安培技术时，观察到电极具有可重复性，标准偏差为 1％。