Separation of Complex Materials by Field-Flow Fractionation

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This project is in the general area of analytical and surface chemistry and in the subfield of separation science. The objective of this research is the continuing development of the science and technology of field-flow fractionation (FFF) and related methods; this work will be carried out in four subareas. (1) Thermal FFF Characterization of Polymeric Materials. In this area, the underlying thermal diffusion processes that are essential to thermal FFF will be characterized. A coupled column- channel system will be developed using a combination of thermal FFF and size exclusion chromatography to characterize the composition and molecular weight distribution of copolymer blends. Thermal FFF will be optimized for high-speed polymer analysis and the applicability of this technique to ultra-high molecular weight polymers will be explored. (2) High Speed Flow/Steric (Hyperlayer) FFF. Work on this recently developed technique will be performed with the objective of optimizing, calibrating, extending the range, improving the repeatability, exploring practical applications, and understanding the basic forces that govern the performance of these new systems. (3) Split-Flow Thin (SPLITT) Continuous Separation Cells. In this thrust, SPLITT separations based on diffusive, sedimentation, and electrical transport processes will be explored with special emphasis on scale-up to a practical preparative level. (4) New FFF Theory and Methodology. Here, Professor Giddings will continue his pursuit of new FFF techniques along both theoretical and experimental lines. Continued attention will be paid to refining the theoretical basis for FFF separations. This research continues the Principal Investigator's development of analytical and preparative separations of complex, high molecular weight materials by several FFF variants. Each of these FFF methods offers unique advantages which, when appropriately matched to the problem at hand, can give rise to enhanced analytical capability. Whereas the complexity of implementation of these techniques has thus far impeded their broad adoption, the sheer power of the methods places them significantly above competitive approaches for the characterization of polymeric substances of key importance to materials and biotechnological processes. The continued development of FFF techniques will provide a formidable arsenal of analytical and preparative tools for use in these technologically important areas. Additionally, Professor Giddings' continued demonstration of the broad applicability of these tools should expedite their adoption by the materials and bioscience communities.