Reconstruction and hydrophobicity of nanocarbon surfaces composed solely of graphene edges

An important minority class of carbon materials selfassemble in a manner that leaves ordered graphene layers lying perpendicular to the outer material surface. These materials include mesocarbon microbeads, platelet carbon nanofibers, and a variety of new liquidcrystal-derived forms including nanofibers, nanotubes, mesoporous carbons, nanoparticles, and anisotropic carbon thin films. These carbon and nanocarbon forms with exposed graphene edge surfaces may be expected to have interesting surface properties that include high chemical reactivity, high surface energy, and enhanced wetting. The most important wetting liquid is water since aqueous phase interactions govern dispersion, nanotube fluidics, and a variety of biological applications in which carbon nanomaterials interact with proteins, DNA, lipid bilayers, and cell surface receptors all in aqueous media. This letter reports new data on the hydrophobicity/ hydrophilicity of new all-edge carbon nanomaterials and relates these property trends to the formation and evolution of atomic surface reconstruction features. Here we study the structure of these edge-plane-surfaces to gain insight into the origin of their hydrophobicity after annealing.