FRG: Fullerene Nanotube Chemistry

William Marsh Rice University, Houston TX

Investigators

Abstract

The focus of this Focused Research Group proposal will develop the molecular science of fullerene nanotubes. These new materials have been hailed for their materials properties and the applications that these properties promise. The single greatest impediment to realizing this promise is the current poverty of chemical approaches for manipulating the tubes as individual molecules. Single-walled nanotubes (swnts) are truly molecular entities, owing to their high degree of structural perfection, but the molecular science of manipulating them in the sense that chemists manipulate other molecules is still quite embryonic. These manipulations include solubilization, covalent derivatization of tube ends and sides, sorting by length, electrical type, and diameter, assembly, cutting, and synthesis of tubes of specific helicity. These are the tasks that comprise the basis of nanotube manipulation, and are central technologies in the realization of the promise of swnt. One particular aim will be to develop a variety of strategies to solubilizing nanotubes in various solvents, including water, by supramolecular routes. Associations of swnts with other molecules will be designed - e.g., polymers or large macrocyclic compounds - both for solubilizing the tubes and for assembling them without making any covalent attachment to their sides, thus preserving fully their intrinsic materials properties. Sorting tubes by length, type, and diameter will be crucial to fulfilling hopes of using nanotubes as wires in molecular electronics. Crude separations by length and diameter have begun, but cleaner, scalable chromatographic and electrophoretic methods are needed. Sorting by electrical type will be approached by exploiting their different electrical and magnetic properties(e.g., using electrophoresis, electrochemistry, and electric or magnetic field gradients), as well as their structural differences to derivatize selectively by type. A grand challenge is to synthesize tubes of a given electrical type. The plan is to utilize seed crystals of a particular type, (separated by methods developed as part of the proposed work), and use covalent chemistry at the end to assemble a catalyst for growth there. This challenge will make demands on several of the other goals, providing both a rich driving force, and, if successful, a remarkable new materials science with far-reaching technological impact. %%% This Focused Research Group project will have a major impact in a fast-breaking area focused on the development of the molecular science of fullerene nanotubes. The research is highly synergistic, multidisciplinary, high-risk and high-impact, with a significant probability for technological payoff in areas that include molecular electronics and high performance composites. This team of intrnationally renown experts is being jointly supported by The Office of Mulitdisciplinary Affairs, The Division of Materials Research and The Chemistry Division of The Mathematical and Physical Sciences Directorate, and by the Division of Chemical and Transport Systems of The Engineering Directorate.