Zhang Yupu, Forrest Tara, Wu Yaotian, Maroni Plinio, Bakker Eric
Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland.
Anal Chem. 2025 Aug 26;97(33):17917-17920. doi: 10.1021/acs.analchem.5c01986. Epub 2025 Aug 11.
Solid-contact ion-selective electrodes (SC-ISEs) are widely used in clinical diagnostics devices and are expanding into other fields including environmental and wearable sensors. Despite significant materials research efforts, the most widely used polymer for membrane preparation remains plasticized poly(vinyl chloride) (PVC). Owing to its nonreactive nature, it is normally applied onto the electrode substrate by evaporative solvent casting. Unfortunately, the resulting films tend to adhere poorly onto the electrode substrate and it is difficult to fabricate robust, well-defined sensing films with controlled thickness down to the nanoscale. This work introduces, for the first time, a PVC polymer membrane that is chemically bonded to the electrode substrate by Cu(I)-catalyzed azide-alkyne cycloaddition (click chemistry). A molecularly thin PVC membrane in which a fraction of the chlorine atoms of the PVC are replaced by azide functionalities is covalently attached to an electropolymerized PEDOT substrate containing alkyne groups by click chemistry. Electrochemical quartz crystal microbalance studies during the electropolymerization and membrane click reaction procedures suggest layer thicknesses of 776 and 42 nm of the conducting polymer and PVC membrane layer, respectively. Once doped with plasticizer and ion sensing components, the ultrathin PVC membrane exhibited a near-Nernstian response slope and excellent ion selectivity. Analytical properties were further improved by overcoating the PVC film with solvent cast PVC, resulting in a standard deviation of the value for potassium-selective electrodes of 1.60 mV.
固态接触离子选择电极（SC-ISEs）广泛应用于临床诊断设备，并正在扩展到其他领域，包括环境传感器和可穿戴传感器。尽管在材料研究方面付出了巨大努力，但用于膜制备的最广泛使用的聚合物仍然是增塑聚氯乙烯（PVC）。由于其惰性，通常通过蒸发溶剂浇铸将其应用于电极基板上。不幸的是，所得薄膜往往与电极基板的附着力较差，并且难以制造出坚固、明确且厚度可控至纳米级的传感薄膜。这项工作首次引入了一种通过铜（I）催化的叠氮化物-炔烃环加成反应（点击化学）与电极基板化学键合的PVC聚合物膜。一种分子级薄的PVC膜，其中PVC的一部分氯原子被叠氮官能团取代，通过点击化学与含有炔基的电聚合PEDOT基板共价连接。在电聚合和膜点击反应过程中的电化学石英晶体微天平研究表明，导电聚合物和PVC膜层的厚度分别为776和42纳米。一旦掺杂有增塑剂和离子传感成分，超薄PVC膜表现出近能斯特响应斜率和优异的离子选择性。通过用溶剂浇铸的PVC覆盖PVC膜进一步改善了分析性能，使得钾选择性电极的 值标准偏差为1.60 mV。
