This project is in the general area of analytical and surface chemistry and in the subfield of chemical modification of surfaces. The primary thrust of this research effort is to investigate in detail the chemical reactions by which the surfaces of silica can be chemically tailored with silanes to produce products and processes of broad scientific, technological, and industrial importance. Among these are chromatographic stationary phases for the efficient separation of products in chemical and biotechnological manufacture, and catalysts for the economically and energetically favorable synthesis and processing of materials. The research strategy will focus first on the solution chemistry of the alkoxysilanes that are used in surface modification processes. The thermodynamics and kinetics of physisorption of these alkoxysilanes on silica will then be studied by thermochemical and chromatographic techniques to elucidate the role of such "pre-reaction encounters" in the overall sueface modification process. The extent to which the reactions of alkoxysilanes with silica surfaces can be catalyzed, either as solution/solid or as gas/solid reaction systems, will then be explored. Finally, the results of these studies will be utilized to develop dynamic computer models with which the silane modification of silica surfaces can be more fully understood and with which optimal reaction conditions for desired surface modification processes can be predicted.