Development of gradient-based surface methods
This work is a detailed study concerning the development and investigation of surface electric field gradients to spatially control the magnitude and locale of electrochemical reactions on surfaces. It will be illustrated that the use of surface potential gradients enables the simultaneous driving of both oxidation and reduction reactions on the same electrode surface. We anticipate that these features will have broad impact over a wide range of applications including microscale devices, sensors, analytical testing devices, and biological applications requiring spatial control of electrochemical phenomena. One example which will be presented in this work of such an application is the development of a spatially controllable pH gradient within a microfluidic channel for isoelectric focusing. Spatial control will also be demonstrated for the local control of adsorbates. In particular, surface potential gradients are used for the maskless patterning of polymers for corrosion protection and sensor applications. Further exploration will delve into the spatial control of metal supported phospholipids, a model system for biological membranes. One final application of surface electric fields will consist of the spatial control of metal electrodeposition and spatiotemporal control of passivating metal oxide film growth, important in studies of catalysis. A separate project will also be discussed concerning the fabrication of low precious metal content monolayer coated nanoscale catalysts for applications in fuel cells. This project utilizes recently developed redox replacement reactions to reduce the amount of catalytic platinum used to only a single monolayer.