  We demonstrate a simple and effective technique for dispersing pristine
(unfunctionalized) graphene at high concentrations in a wide range of organic
solvents by use of a stabilizing polymer (polyvinylpyrrolidone, PVP). These
polymer-stabilized graphene dispersions are shown to be highly stable and
readily redispersible even after freeze-drying. This technique yields
significantly higher graphene concentrations as compared to prior studies.
Excellent enhancement in thermal conductivity of the fluid by addition of
pristine graphene is also demonstrated. These well-dispersed pristine graphene
sheets were then used as a strong and conductive nano-filler for polymer
nanocomposites. PVP/graphene nanocomposites were produced via bulk
polymerization of N-vinylpyrrolidone loaded with dispersed graphene, resulting
in excellent load transfer and improved mechanical and electrical properties.
