Discovery of effective solvents for platelet-type graphite nanofibers

The dispersibility of platelet-type graphite nanofibers (PGNFs), an archetype of carbon material with a surface dominated by graphitic edge planes, has been measured in 28 solvents and rationalized on the basis of solvent surface tension and Hansen solubility parameters. Successful solvents possess surface tensions of ∼25–35 mJ m−2 and substantial values of the hydrogen-bonding Hansen parameter (δH ∼ 14–16 MPa1/2), and many of them are alcohols, such as 1-butanol, ethanol or cyclohexanol. Such result is mainly attributed to the fact that the PGNF edge planes are decorated with oxygen functional groups. The dispersion behavior of the nanofibers could be changed to that typically exhibited by carbon nanotubes and graphene by means of a high temperature annealing that converted their surface edge planes to curved basal planes.