Single walled carbon nanotubes (SWCNTs), due to their diverse and superlative electronic properties, are considered the best candidate to replace silicon as the backbone of the semiconducting and electronic industry. All of the current upstream synthesis techniques result in production of mixtures of metallic and semiconducting SWCNTs. This creates impediments to their application as transistors, which require extremely high-purity fractions of semiconducting SWCNTs. Therefore, there is a great need to develop methods to separate mixtures of metallic and semiconducting nanotubes into highly enriched fractions of single electronic types. Experimental complexity, lack of scalability, and the lack of understanding about the underlying mechanisms of the current downstream separation techniques have motivated our research group to design simple and scalable chromatographic based separation methods which rely upon conventional chromatographic materials such as ion exchange, hydrophobic, and mixed mode materials in order to achieve separations of metallic and semiconducting nanotubes. In this work, we have demonstrated that the upstream purification steps, which generally are implemented to separate non-SWCNTs impurities, confer to nanotubes ionic characteristics in addition to their inherent hydrophobic structures. The induced surface charges and inherent hydrophobic surfaces of the SWCNTs were directly exploited via traditional chromatographic materials and methods, and as a result separated fractions of metallic and semiconducting SWCNTs were obtained.
Keywords: Single walled carbon nanotubes, Separation, Chromatography
- Design and development of separation techniques such as liquid chromatography, aqueous two phase polymer extraction, density gradient ultracentrifugation, and filtration in order to purify and separate various nanomaterials (such as SWCNTs), and bio-macromolecules (such as proteins)
- Investigation of macromolecular interactions via molecular modeling techniques such as docking and molecular dynamics
- Model-based design of high resolution chromatofocusing technique
- Transport phenomena
- Separation processes
- Chemical engineering design