The synthesis of single-walled carbon nanotubes with narrow diameter distribution using polymerized hemoglobin

Single-walled carbon nanotubes (SWCNTs) with a narrow diameter distribution were synthesized by using polymerized hemoglobin (PolyHb). PolyHb containing 11 Hb molecules (11-PolyHb) was separated from a mixture of PolyHb with various degrees of polymerization by using size-exclusion chromatography (SEC). After the deposition and oxidation of 11-PolyHb, we obtained iron oxide nanoparticles with an average diameter of 1.30 ± 0.36 nm. SWCNT were grown from these nanoparticles with a narrow diameter distribution, 1.08 ± 0.26 nm. This technique has the potential to synthesize SWCNT with an identical diameter, and to control the diameter of SWCNT at atomic resolution through improvements to the SEC processing.