Emerging applications require single-wall carbon nanotubes (SWCNTs) of welldefined length. Yet the use of length-defined SWCNTs is limited, in part due to the lack of an easily accessible materials preparation method. Here, we present a new strategy for SWCNT length fractionation based on molecular crowding induced cluster formation. We show that the addition of polyethylene glycol (PEG) as a crowding agent into DNA-wrapped SWCNT dispersion leads to the formation of reversible, nematic, and rodlike microclusters, which can be collected by gentle centrifugation. Since shorter SWCNTs form clusters at higher polyethylene glycol concentration, gradual increase in PEG concentration results in length fractionated SWCNTs. Using atomic force microscopy (AFM) we show that fractions with average lengths of 60500 nm and standard deviations of 3040% can be obtained. The concept of molecular-crowding-based fractionation should be applicable to other nanoparticle dispersions.
Citation: ACS Nano
Pub Type: Journals
carbon nanotube, DNA, molecular crowding, depletion forces, self-assembly