New development in solvothermal reduction of alkyl-functionalised sub-oxidized graphene oxide
14 May 2012. ONDL scientist Zhi-Li CHEN announces the successful development of “surfactant-free” and “chemical reducing agent-free” 200ºC solvothermal reduction of alkyl-functionalized sub-oxidized graphene oxide in mixed solvent trichlorobenzene and amide solvents at the European Material Research Society (E-MRS) spring meeting today. No further purification is needed after reduction. The reduced graphene oxides have alkyl-chains that survive the thermal heating therefore they are still dispersible in organic solvents and compatible with general solution-processable deposition techniques. “These alkyl-functionalized reduced graphene oxides are particularly useful for plastic substrate that cannot survive high temperature treatment. They can also be dispersible in polymer solutions to form graphene-polymer nano-composite films" says Zhi-Li CHEN. Further this dispersion can be spin-coated to form high quality film that showed good adhesion to substrate. The film survives scotch-tape test. This is because the sheets are being laid down layer-by-layer and not as aggregates. The film gives electrical conductivity of about 50 Scm-1, similar to those reported in the literature using solution reduction methods hence their conductivity is not limited by the presence of alkyl chains that are still on the sheets which is important for their dispersability. The reduction mechanism here is the result of thermal heating and also the presence of carbon monoxide (CO) gas reductant when amide solvent decomposes to give CO at elevated temperature.