  We have demonstrated a method to disperse and exfoliate graphite to give
graphene suspended in water-surfactant solutions. Optical characterisation of
these suspensions allowed the partial optimisation of the dispersion process.
Transmission electron microscopy showed the dispersed phase to consist of small
graphitic flakes. More than 40% of these flakes had <5 layers with ~3% of
flakes consisting of monolayers. These flakes are stabilised against
reaggregation by Coulomb repulsion due to the adsorbed surfactant. However, the
larger flakes tend to sediment out over ~6 weeks, leaving only small flakes
dispersed. It is possible to form thin films by vacuum filtration of these
dispersions. Raman and IR spectroscopic analysis of these films suggests the
flakes to be largely free of defects and oxides. The deposited films are
reasonably conductive and are semi-transparent. Further improvements may result
in the development of cheap transparent conductors.
