Stable Aqueous Suspension and Self‐Assembly of Graphite Nanoplatelets Coated with Various Polyelectrolytes

Abstract

Exfoliated graphite nanoplatelets (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 polyelectrolytes. The surfactants and polyelectrolytes were compared with respect to their ability to suspend graphite nanoplatelets. The surface charge of the nanoplatelets 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 nanomaterial 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.

Experimental and computational investigation of reduced graphene oxide nanoplatelets stabilized in poly(styrene sulfonate) sodium salt

“…This interaction should be strong enough to trap the styrene groups and, thus, hamper the vibration of PSS chain as suggested by FTIR analysis. These results are in good agreement with Raman analysis[54] indicating that there is a trend to PSS accommodation close to rGO nanoplatelet without chemical reaction.After characterization of GPSS and GO composites, PAH polyelectrolyte was used to build up both (PAH/GO) and (PAH/GPSS) LbL nanostructures. LbL film growth was investigated using UV-vis absorption spectroscopy, illustrated inFigure 6.…”

Investigation on the use of graphene oxide as novel surfactant to stabilize weakly charged graphene nanoplatelets

“…In addition, GnP is generally known to have much preserved aromatic structure on its basal plane which is hydrophobic in nature. In this context, the colloidal stability is only provided by its parametric edges which is more hydrophilic due to existence of water-based functional groups [51,52]. Therefore, the competing repulsive electrostatic and attractive van der Waals forces between GnP particles and GO sheet result in large fluctuation of measured zeta potential.…”

“…Graphene nanoplatelets (GnP) have recently attained immense attention from research community due to its resemblance to idealized graphene in terms of chemical and morphological structure [51][52][53][54]. This material is produced from microwave expansion of acid intercalated graphite which yields a planar structure with average thickness of 1 to 10 nm and varying diameter of 15 to 50 microns [55][56][57].…”

“…Thus, it can be said that the solubility of GnP is size-dependent since more functional groups exist in larger size sheets which contain more structural defects sites [66]. The presence of these functional groups also paves avenues for further covalent and non-covalent functionalization to enhance its solubility [52,67].…”

Ultra-Thin Films of Reduced Graphene Oxide (RGO) Nanoplatelets Functionalized with Different Organic Materials

“…On the other hand, it was noticed physical interaction (van der Waals) between PSS and rGO nanoplatelets since no new bands or peak shifts were observed in the GPSS spectrum compared with the neat materials spectra; the GPSS spectrum can be called a sum of the bands observed at the PSS and rGO spectra. Very small shifts were observed, for instance from 1128 to 1132 cm -1 possibly due to hydrophobic interactions between the sp 2 network in the nanoplatelets with the benzene ring in PSS [23]. No conclusions can be drawn in this region since it is inside the equipment error (4 cm -1 ), reinforcing the physical interaction nature of these interactions.…”