Current SWCNT production techniques yield polydisperse samples containing many different types SWCNTs, defined by differing chiralities and lengths. Thus it is important to develop methods to produce well-characterized fractions of carbon nanotubes with controlled parameters (length, diameter, chiral angle, charge, concentration and purity), so that vendors and buyers can trade SWCNT with confidence. These methods can be collectively categorized as Nanotube Metrology. Characterization of nanotubes is critical in order to advance applications and to enable well-controlled environmental, health and safety (EHS) assessments.

National Institute of Standards and Technology (NIST) leads an ongoing collaboration among various industrial, academic and government researchers to develop such methods, and to define reference standards. These efforts were recently highlighted at a NIST-sponsored workshop. NIST also has published a Recommended Practice Guide which launched the extensive ISO activities in SWCNTs. Prof. Weisman, through his activities at Rice University and ANF, continues to make valuable contributions to this effort.