We have used for the first time a conjugated redox polymer with hydroquinone (HQ) pendant groups covalently attached to the poly(3,4-ethylenedioxythiophene) (PEDOT) backbone as the solid contact (SC) in plasticized poly(vinyl chloride) (PVC) based K⁺-selective electrodes (K-SCISE). Redox couples are one of the simplest ways to precisely adjust the standard potential (E°) of the SCISEs, but usually the initially high E° reproducibility is lost quite quickly due to leaching out of non-covalently bound redox molecules from the SCISE. In PEDOT-HQ, the covalently attached HQ groups prevent the leaching and simultaneously allow additional charge storage in PEDOT-HQ that is ca. 25-30 times higher than for unsubstituted PEDOT. Before the ion-selective membrane (ISM) deposition, we controlled the potential of the SC with high reproducibility (±0.4 mV, n = 5) by pre-polarization in a mixture of acetonitrile containing potassium tetrakis(pentafluorophenyl)borate and perchloric acid as proton source. Pre-polarization of the SC close to the formal potential where the redox buffer capacity is highest gave the best potential reproducibility. However, after the ISM deposition, the K-SCISEs showed in the best case an E° reproducibility of ±2.8 mV (n = 5). Chronopotentiometric measurements reveal that only a minor fraction of the very high redox capacitance of PEDOT-HQ can be utilized for the ion-to-electron transduction beneath the ISM. The influence of this shortcoming on the E° reproducibility of the SCISEs has been underestimated for most SC materials. Modification of the commonly used PVC-ISM formulations to allow faster ion transfer at the SC/ISM interface could be one way of overcoming the disadvantage.

我们首次使用了共轭氧化还原聚合物和对苯二酚（HQ）侧基共价连接到聚（3,4-乙撑二氧噻吩）（PEDOT）主链上，作为增塑聚氯乙烯（PVC）中的固体接触（SC） ）的K ⁺ -选择电极（K-SCISE）。氧化还原对是精确调节SCISE的标准电势（E °）的最简单方法之一，但是通常最初会提高E由于从SCISE中析出了非共价结合的氧化还原分子，因此很快丧失了可重复性。在PEDOT-HQ中，共价连接的HQ基团可防止浸出，并同时允许在PEDOT-HQ中额外存储电荷，约为。比未取代的PEDOT高25-30倍。在离子选择膜（ISM）沉积之前，我们 通过在包含四（五氟苯基）硼酸钾和高氯酸的乙腈混合物中预极化，以高再现性（±0.4 mV，n = 5）控制了SC的电位。质子源。SC的预极化接近氧化还原缓冲液容量最高的形式电位，具有最佳的电位重现性。但是，在ISM沉积之后，K-SCISE在最佳情况下显示E°重现性为±2.8 mV（n  = 5）。计时电位测量法显示，PEDOT-HQ的非常高的氧化还原电容中只有一小部分可用于ISM下方的离子到电子的传导。对于大多数SC材料，这种缺点对SCISE的E °重现性的影响被低估了。修改常用的PVC-ISM配方以允许在SC / ISM界面更快地进行离子转移可能是克服这一缺点的一种方法。