Integration of evanescent wave cavity ringdown spectroscopy with electrochemical methods: A step change in the study of interfacial phenomena

界面是两个相之间形成的区域，当它们被带到一起时不会混合。界面具有独特的物理和化学性质，在许多科学领域具有基本和实际的重要性。例如，固/液和液/液界面可用于催化、合成和传感应用。在生命系统中发现了更复杂的界面，例如形成生物细胞主要成分的膜。由于界面区域非常薄（纳米级;比人的头发细50，000倍），并且当它交叉时，它的属性会突然改变，因此我们对界面的信息要比均匀的体相（固体，液体和气体）少得多。为了理解和探测界面，科学家需要能够揭示界面性质的新技术。我们的建议是建立一个新的仪器，结合了两种方法，已分别应用于不同领域的科学-扫描电化学显微镜（SECM），可以测量发生在溶液中的表面的反应速率，和化学表征方法称为倏逝波腔衰荡光谱（EW-CRDS）。每种方法都有不同的属性，通过第一次将它们放在一起，我们希望找到关于广泛的重要界面过程的新信息。该方法简单但功能强大：SECM将用于扰动界面或以定义明确的方式在局部尺度上驱动界面过程，而EW-CRDS将以高灵敏度确定作为扰动结果的化学反应。在这个令人兴奋的新开发中，我们将花费部分项目来构建和测试仪器，然后将该方法应用于四个不同的领域，以说明我们期望产生的新信息的广度。我们将研究：（i）模拟生物膜，以发现质子如何沿着膜表面移动，这是活细胞功能的关键过程;（ii）电荷如何在导电聚合物膜中移动，这有可能用于新一代电子器件和传感器;（iii）金属如何在油和液体之间的区域形成和生长，以更好地理解纳米颗粒的形成。我们还将研究是否有可能研究金属电极表面，这将开辟电化学研究的主要领域，最终有可能研究催化剂和传感器表面的作用。

An interface is the region that forms between two phases that do not mix when they are brought together. Interfaces have unique physical and chemical properties, that are of fundamental and practical importance throughout many areas of science. For example, solid/liquid and liquid/liquid interfaces can be used for catalysis, synthesis and sensing applications. More complex interfaces are found in living systems, such as membranes which form a major component of biological cells. Since the interfacial region is so thin (nanometer scale; 50,000 times thinner than a human hair), and its properties change abruptly as it is crossed, we have much less information on interfaces than on uniform bulk phases (solids, liquids and gases). To understand and probe interfaces, scientists require new techniques that can uncover the properties of interfaces. Our proposal is to build a new instrument that combines two approaches that have been applied separately in different areas of science - scanning electrochemical microscopy (SECM) which can measure rates of reactions occuring at surfaces in solution, and a chemical characterisation method called evanescent wave cavity ring down spectroscopy (EW-CRDS). Each method has distinct attributes and by bringing them together for the first time, we expect to find new information on a wide range of important interfacial processes. The approach is simple but powerful: SECM will be used to perturb an interface or drive an interfacial process on a local scale in a well-defined way, while EW-CRDS will determine with high sensitivity what happens chemically as a result of the perturbation. In this exciting new development, we will spend part of the project constructing and testing the instrument and then apply the method to four different areas, to illustrate the breadth of new information that we expect to result. We will study: (i) model biological membranes, to discover how protons move along the membrane surface, which is a key process in the functioning of living cells; (ii) how charges move in ultrathin conducting polymer films, which have the potential to be used in a new generation of electronic devices and sensors; (iii) how metals form and grow in the region between an oil and a liquid, to better understand the formation of nanoparticles. We will also investigate whether it is possible to study metal electrode surfaces, which would open up major areas of electrochemistry for study, with the ultimate possibility of investigating catalyst and sensor surfaces in action.