Electrochemical anion sensing at self-assembled monolayers and polymeric interfaces

自组装单层和聚合物界面的电化学阴离子传感

• 批准号: 2446622
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2446622
• 关键词: Electrochemical; anion; sensing; self; assembled

Anionic species are relevant targets in a multitude of fields for biological, medicinal and environmental applications. Thus, there is significant demand for the development of approaches for selective, sensitive and practically applicable anion sensing, particularly in competitive media (which is required for most real-world applications). Electrochemical methods (voltammetric, impedimetric or potentiometric) provide a powerful yet relatively experimentally simple approach to probe synthetic receptors in solution or at interfaces, which would be otherwise challenging to probe with other routinely used techniques like NMR or UV-Vis spectroscopy. Immobilisation of a sensor onto a surface (often in self-assembled monolayers, SAMs) offers a number of advantages, including bypassing receptor solubility limits, significantly reducing the quantity of receptor required and can also provide a sensing amplification due to preorganisation and dielectric effects at an interface. The anion sensing capabilities of a number of anion receptive, redox-active receptors have been investigated thus far (often containing hydrogen bonding (HB) binding sites) but an area which is largely underdeveloped is interfacial, electrochemical sensing of anions with halogen bonding (XB) based receptive motifs. Halogen bonding has been shown to be a strong, directional non-covalent interaction that often outperforms HB analogues and therefore presents an opportunity to improve anion sensor designs. Further to this, an exploration of receptive, polymeric interfaces with XB motifs offers an investigation into possible multivalent, dielectric and electric field effects that could greatly influence the efficacy of anion binding/sensing at an interface. This project aims to investigate the anion binding capabilities of self-assembled monolayers with HB/XB-based binding motifs (e.g. proto- or iodotriazoles) via various electrochemical techniques (particularly voltammetric and impedimetric sensing), and then progress to studying interfacial electrochemical anion sensing under flow, which is unprecedented for a sigma bonding interface. A systematic study with a range of anions will be conducted in competitive solvent media (ACN/H2O systems) and comparisons will be drawn between HB and XB analogues. Furthermore, a comparison between discrete receptors in SAMs and polymeric films with a similar redox-active, XB-based design will be investigated. A methodology will be developed for surface-initiated polymerisation of this receptive monomer motifs (both redox-tagged and not) using a controlled radical polymerisation procedure such as atom transfer radical polymerisation (ATRP) or reversible addition-fragmentation chain-transfer polymerisation (RAFT). This will be followed by extensive characterisation of the resulting films (e.g. polydispersity, film thickness, voltammetric behaviour) and comprehensive electrochemical sensing studies for a range of anionic species.This project falls within the EPSRC Physical Sciences research area: analytical science, electrochemical sciences, polymer materials.

阴离子物种是许多生物、医学和环境应用领域的相关靶标。因此，对开发选择性、灵敏和实用的阴离子传感方法有很大的需求，特别是在竞争性介质中(这是大多数现实世界应用所必需的)。电化学方法(伏安法、阻抗法或电位法)提供了一种强大但在实验上相对简单的方法来探测溶液中或界面上的合成受体，否则使用其他常规使用的技术如核磁共振或UV-Vis光谱进行探测将具有挑战性。将传感器固定在表面上(通常是在自组装单分子膜中)具有许多优点，包括绕过受体溶解度限制，显著减少所需的受体数量，还可以由于界面上的预组织和介电效应而提供传感放大。到目前为止，许多阴离子受体的阴离子感知能力已经被研究过(通常包含氢键(HB)结合位点)，但一个很不发达的领域是基于卤素键(XB)的阴离子接受基序的界面电化学传感。卤素键已被证明是一种强的、定向的非共价相互作用，通常比Hb类似物性能更好，因此为改进阴离子传感器设计提供了机会。此外，探索具有XB基序的感受性聚合物界面提供了对可能的多价、介电和电场效应的研究，这些效应可能会极大地影响界面上的阴离子结合/传感的效果。本项目旨在通过各种电化学技术(特别是伏安和阻抗传感)研究具有HB/XB结合基序的自组装单分子膜(例如原始或碘三唑)的阴离子结合能力，进而研究流动条件下的界面电化学阴离子传感，这在Sigma键合界面上是前所未有的。将在竞争性溶剂介质(ACN/H2O体系)中对一系列阴离子进行系统研究，并对HB和XB类似物进行比较。此外，还将研究自组装膜中的离散受体与具有类似氧化还原活性的XB设计的聚合物膜之间的比较。将开发一种方法，用于使用受控自由基聚合程序(如原子转移自由基聚合(ATRP)或可逆加成-断裂链转移聚合(RAFT))表面引发聚合该受体单体基序(包括氧化还原标记和非氧化还原标记)。随后将对所得薄膜进行广泛的表征(如多分散性、薄膜厚度、伏安行为)，并对一系列阴离子物种进行全面的电化学传感研究。该项目属于EPSRC物理科学研究领域：分析科学、电化学科学、聚合物材料。