Study On The Functionalization And Preliminary Application Of Graphene Oxide

Graphene is a novel two-dimensional nanomaterial which could be seen as one-atom-layer graphite. Because of the specific structure, graphene has shown several outstandingmechanical, electrical,optical and chemical properties. Graphene Oxide (GO) is an intermediate productin the process of preparing graphene through chemical oxidation-exfoliation reduction method. The strong oxidation treatmentgenerates many oxygen-containing groups, suchas carboxyl groups and hydroxyl groups, which endows GO several characters different from graphene.Having excellent properties, the problem of poor dispersion stability hinders its application greatly. Meeting with this issue, many researchers from different fields have been working on it, and several methods for the functionalization of graphene has been developed since the first report about the gorgeous nanomaterial was published in2004.In this thesis, several attempts was taken to functionalize graphene/GO, and the modified material was put into use preliminarily according to its characters. The thesis contains five chapters.Chapter1is the general introduction about the structure&properties of graphene/GO as well as the recent progress in the synthesis, the functionalization&the application of graphene/GO.In chapter2, GO was prepared using the chemical oxidation-exfoliation method in the first place; then, using ethanediamine&PEG for the functionalization of GO simultaneously, the EDC/NHSactivation method was taken as the amidation way instead of the acyl-chloride method considering the effectiveness, the obtained NH2-GO-PEG was able to be dispersed steadily in the Buffer Solution; then it was tentatively used as the carrier for the anti-cancer drug delivery.In chapter3, Stimuli-responsive polymers, poly(acrylic acid) andpoly(N-isopropylacrylamide), were covalently grafted onto thesurface of graphene oxide through a facile redox polymerizationinitiated by cerium ammonium nitrate in aqueous solution at mildtemperature.The covalently grafted poly-(acrylic acid) and poly(N-isopropylacrylamide) afforded pH andthermal responsibility to graphene oxide, and the assemble-disassemblebehaviors of polymer-grafted graphene oxide in aqueoussolution could be controlled by varying the pH or temperature of the solution,besides, the graft ratio could be adjusted by simply change the feed amount of the monomers among the proper range.In chapter4, graphene was used in lithium ion battery (LIB). On the one hand, graphene/N-methylpyrrolidone (NMP) dispersion was prepared through chemical oxidation-reduction method using polyvinylpyrrolidone (PVP) as the stabilizer, the obtained material shows similar performance at a lower feed ratio when being used as the conductive agent of LIB anode material; on the other hand, with a different core thought, LiFePO4/graphene composite was synthesized using carbonthermal reduction method and hydrothermal method separately, the XRD result confirmed the successful preparation of LiFePO4while the capacity test reveals the synthetic process still needs to be optimized.Chapter5is the conclusion of the whole research work.Using different functionalization methods, graphene oxide was modifided successfully, the obtained functionalized material could have potential applications in the drug-delivery system&lithium ion battery seperately.