Stable Aqueous Suspension and Self-Assembly of Graphite Nano platelets Coated with Various Poly electrolytes

Exfoliated graphite nano platelets (xGnPs) with an average thickness of 1-10 nm present an inexpensive alternative to carbon nanotubes in many applications. In this paper, stable aqueous suspension of xGnP was achieved by noncovalent functionalization of xGnP with poly electrolytes. The surfactants and poly electrolytes were compared with respect to their ability to suspend graphite nanoplatelets. The surface charge of the nano platelets was characterized with zeta potential measurements, and the bonding strength of the polymer chains to the surface of xGnP was characterized with Raman spectroscopy. This robust method opens up the possibility of using this inexpensive nano material in many applications, including electrochemical devices, and leads to simple processing techniques such as layer-by-layer deposition. Therefore, the formation of xGnP conductive coatings using layer-by-layer deposition was also demonstrated.