Role of poly(N-vinyl-2-pyrrolidone) as stabilizer for dispersion of graphene via hydrophobic interaction

Stable aqueous dispersion of chemically reduced graphene is simply obtained by reducing GO solution in the presence of PVP. Prepared aqueous graphene dispersion was optically clear and stable for several months without any aggregation or precipitation. Graphene/PVP assembly shows decreased optical transmittance (47% at 600 nm) and quenching of photoluminescence of parent GO (8.5% at 375 nm) after reduction. Raman analysis confirms that reduction of GO to graphene is efficient in the presence of PVP. Both DLS and AFM analysis confirm that there is efficient and overall interaction between chemically reduced graphene plates and PVP chains. Hydrophobic interaction between graphene and PVP might be responsible for this solubilization of chemically reduced graphene in solution.