Scanning Potential Microscope for Spatial Imaging

Gilbert, Jeremy

Abstract

This is a proposal to build and use a potential (voltage) imaging device which can scan the surface of a metallic sample on a microscopic level to spatially resolve and image the local -action corrosion, stress -assisted corrosion and other electrochemical mechanisms that may be present in various biomaterials. With slight modifications of the detection method, this instrument could also use the conduction of ions to image non-conducting polymers and ceramics. This instrument is not commercially available and is only now in the development stage at several research institutions. This type of instrument has not, as yet, been utilized in the study of biomaterials. This effort would be the first attempt to do so. There are a wide range of applications to which an instrument of this type could be applied to characterize and understand biomaterials and their interactions with various local environments. This instrument could image electrochemical interactions of metal surfaces with ions and proteins. Also, the electrical aspects of a cell, attached to a biomaterial could be imaged, in real time, providing a means of directly observing this interaction. While prototypes of this type of device have been developed in the past they have not as yet been applied to the study of biomaterial surfaces, the study of dynamic stress conditions (i.e., fracture and fatigue) or in the study of interactions of biomaterials with their environments (tissues, bone etc.). This technique could have far reaching impact on the way researchers address the nature of the biomaterial surface and the understanding of this surface in the dynamic loading and environmental conditions to which it is subjected. Instrument development and image optimization are the primary goals of this proposal. The factors to be explored are: resolution as a function of probe size, sample-probe distance, and probe type. Correlation of images obtained to SEM images will be made to demonstrate the efficacy of this Scanning Potential Microscope.