Grant: Research Tools and Instruments - Category 1 (<$150,000)

The focus of our research program is to describe the molecular-level interaction between solid surfaces and biomolecules attached to these surfaces.  A better understanding of these phenomena will lead to advances in biocompatible materials for use as implants, the development of more efficient biosensors and biodiagnostic tools, and increase our fundamental knowledge of alterations to the native structure of proteins when then encounter foreign materials.  The challenge in such characterization lies in the complexity of the problem---there are many environmental factors that contribute to the biomolecules' structure on a surface. The first step towards an increased understanding is to be able to accurately describe the adsorbed structure of these molecules.  Spectroscopic techniques are among the most powerful tools for probing these structures, since they are non-invasive, non-destructive, and may probe many environments that are addressable by light.  Such methods, however, require a detailed knowledge of the the optical constants of these materials.  The infrared region offers special opportunites for structural studies since localized parts of molecules may be probed.  However, this is also the region in which optical constants are relatively unknown.  The requested instrument is an infrared-visible Mueller-matrix ellipsometer.  It will allow for a simultanous determination of a sample's thickness and complex refractive index over the complete range of wavelengths of interest for chemical identification and structural analysis.  Moreover, the proposed configuration of this state-of-the-art instrument will allow characterization of ordered molecules and rough surfaces.