In this project, funded by the Macromolecular, Supramolecular, and Nanochemistry Program of the Chemistry Division, Prof. Robert Hamers of the University of Wisconsin-Madison and his students will integrate polymer chemistry with surface chemistry to make ultra-stable interfaces between metal oxide nanoparticles and molecular systems such as molecular photocatalysts and light-harvesting molecules. They will explore the synthesis and properties of functional "nano-skins" created on surfaces, using metal oxides such as TiO2 as model systems. In order to form robust layers, molecules bearing multiple reactive groups will be grafted to TiO2 surfaces; these will then be cross-linked to form two-dimensional surface nets in which each surface oligomer has many linkages to the surface. Electrochemically active species will then be linked to the net to form functional layers with novel electrochemical and photoelectrochemical properties. Fundamental properties such as electron transfer rates will be measured using surface-attached ferrocene groups. A variety of experimental measurements will be performed to characterize the chemical and physical properties of the layers in order to establish whether extensive lateral cross-linking within nanometer-thick molecular layers can lead to highly stable interfaces with novel electrochemical and photoelectrochemical properties.
This project will provide graduate students, undergraduate students, and junior scientists with state-of-the-art training in the techniques of surface chemistry and other career skills necessary to become scientific leaders. Students will learn techniques of chemical synthesis, characterization of surfaces, and a variety of electrochemical and photoelectrochemical measurement techniques. They will also receive training in oral and written communication, ethics, and leadership. The research will provide important fundamental insights into charge-transfer processes within and through molecular layers at surfaces and will help to establish design rules for how to fabricate highly stable interfaces between inorganic materials and organic-based molecular structures. Inorganic-organic hybrid structures are of great interest in a range of existing and emerging commercial technologies, and the ability to make water-stable interfaces between molecules and metal oxides such as TiO2 would have both commercial and societal impact in areas such as renewable energy. The project will also impact society by providing opportunities for educational and outreach activities with a diversity of outside groups.
