Title: An Inside Story: Controlling, Separating, and Characterizing the Effects of Filling the Interior of Nanotubes
Abstract: Single-wall carbon nanotubes (SWCNTs) are among the most studied nanomaterials, with almost two decades of work in generating dispersion and separating populations by SWCNT species, enantiomeric handedness and length. An emergent direction in SWCNT research is to additionally control what is in the interior volume of a SWCNT, with the purpose to modify its material properties by changing the local dielectric environment, or to carry cargo molecules for specific functions. In my lab at NIST, we’ve demonstrated that SWCNTs with open ends can be readily filled with a wide variety of organic molecules through simple liquid exposure. Ingestion of these molecules affects the extrinsic environment experienced by the SWCNT, and holds promise for controlled modulation of intrinsic SWCNT properties such as optical linewidth narrowing, transition energy tailoring and fluorescence enhancement. However, the effect to the SWCNT properties for the same filler molecule can be non-uniform across filler and SWCNT (n,m) combinations due to finite host and guest sizes and other higher order effects. In this talk I will present first the general modulation of SWCNT properties through endohedral volume control, drill down into the careful characterization of sieving and size effects using (n,m) separated samples, and finally discuss characterization using analytical ultracentrifugation of the accessible volume size, and alkane packing density in, moderate diameter nanotubes.