A nanostructure having at least one nanotube and at least one chemical moiety non-covalently attached to the at least one nanotube. At least one dendrimer is bonded to the chemical moiety. The chemical moiety may include soluble polymers, soluble oligomers, and combinations thereof. A method of dispersing at least one nanotube is also described. The method includes providing at least one nanotube and at least one chemical moiety to a solvent; debundling the nanotube; and non-covalently attaching a chemical moiety to the nanotube, wherein the non-covalently attached chemical moiety disperses the nanotube. A method of separating at least one semi-conducting carbon nanotube is also described.