Synthesis and Characterization of Novel Hydrogel Formulations for the Single Chirality Purification of Single-Walled Carbon Nanotubes

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program and the Chemical Measurement and Imaging Program in the Division of Chemistry and the Interfacial Engineering Program in the Division of Chemical, Biochemical, Engineering and Transport Systems (CBET), Kevin Tvrdy of the University of Colorado at Colorado Springs is developing novel hydrogel separation media for optimizing the separation and purification of single-walled carbon nanotubes. The project explores the rational design of both relatively expensive hydrogel formulations, based on biologically derived polysaccharides, and relatively inexpensive hydrogel formulations, based on small molecule building blocks.

The metric of success of this project is the degree of purity of the single chirality SWCNs that are isolated using the proposed hydrogel formulations. The availability of pure single component carbon nanotubes of uniform properties has the potential to significantly impact a wide range of applications, in nanoelectronics, biological imaging, photovoltaics and energy harvesting and storage.

Master's level and undergraduate students will be involved in conducting the proposed research. Research results will be incorporated in a nanoscience course and shared with the general public in a monthly "Science on Tap" lecture series designed to promote science literacy and appreciation of science in the Colorado Springs community.

In this project, Kevin Tvrdy and his students seek to develop hydrogel media specifically tailored for the chiral separation of single-walled carbon nanotubes (SWCNTs). Top-down modification of commercially-available Sephacryl hydrogels will be pursued, as well as bottom-up synthesis. Biologically derived polysaccharides will be crosslinked using radical polymerization to form novel hydrogel formulations, and a select group of water-soluble monomers and crosslinkers will be used to form alternative low-cost formulations.

The hydrogel products will be characterized with spectroscopic and microscopic techniques, and their potential for SWCNTs separations based on chirality will be quantified. The metric of success of this project is the degree of purity of the single chirality SWCNTs that are isolated using the proposed hydrogel formulations. By focusing on the rational design of novel hydrogel media, this work seeks both fundamental knowledge of the chirality dependent physiochemical driving forces at the hydrogel/nanotube interface, and application of that knowledge to realize gel formulations tailored for isolation of specific nanotube chiralities.

Achievement of the central goal of this project has the potential to impact how nanotubes are integrated into both fundamental and applied research.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.