PURIFICATION AND CHARACTERIZATION OF DOUBLE WALL CARBON NANOTUBES
Ji Yeon Huh and Jeffrey A. Fagan
Polymers Division, MSEL, NIST, Gaithersburg, MD 20899.
Double wall carbon nanotubes (DWCNTs) consisting of two concentric graphene cylinders exist in an intermediate regime between single- (SWCNTs) and multi wall carbon nanotubes (MWCNTs). Although their diameter of the outer wall is often similar to that of SWCNTs, DWCNTs exhibit advanced mechanical properties and thermal conductivity, which plays a critical role in various thin film applications such as transparent conductors and field-effect transistors. In this work, DWCNTs are purified from polydisperse mixtures of SWCNTs, MWCNTs, and carbonaceous impurities using density gradient ultracentrifugation (DGU). Based on the combination of DGU and the surfactant chemistry utilized to encapsulate and disperse DWCNTs in solution, DWCNTs are sorted by their electronic structure varying from metallic to semiconducting. The length dependent optical properties of DWCNTs are further investigated by maximizing the differences in density between DWCNTs and density gradient medium.
Mentor: Jeffrey A. Fagan
Polymers Division, MSEL
Room A223, Building 224, Mail stop 8542
Is your mentor a Sigma Xi Member? No