Noncovalent functionalization of graphite and carbon nanotubes with polymer multilayers and gold nanoparticles

This paper describes a strategy for functionalizing graphite and carbon nanotube surfaces with multilayered polymeric films. Poly(amphiphiles) adsorb noncovalently onto these surfaces from aqueous solutions, due to hydrophobic interactions. The covalent attachment of a second polymer layer to this initial adsorbed layer results in the formation of a cross-linked polymer bilayer; additional layers can be deposited by the covalent or electrostatic attachment of polyelectrolytes. We used these multilayered polymer films to mediate the attachment of gold nanoparticles to graphite, single-walled nanotube (SWNT), and multiwalled nanotube (MWNT) surfaces. This approach provides a convenient method for attaching other nanostructures, biological molecules, or ligands to carbon nanotubes.