This work focuses on the central concept of producing graphene from graphite without covalently functionalizing the graphene basal plane; such graphene may be stabilized, dispersed, and processed for use in a range of high-performance materials. In particular, our group has shown that both polyvinylpyrrolidone as well as pyrene derivatives can naturally absorb to the graphene surface, create repulsive (steric and electrostatic) forces, and prevent aggregation. This allows for graphene dispersion in a wide range of organic solvents and composite precursors without compromising graphene structure. Such dispersions are stable against aggregation even when subjected to extreme temperature changes, pH changes, and freeze drying. The graphene/stabilizer ratio obtained by this method is exceptionally high relative to conventional surfactants. The mechanism of stabilization by pyrene derivatives were investigated as a function of the type and number of functional groups, counterions, and the electronic interaction between the functional groups and the basal plane.Polymer nanocomposites formed from these dispersions include graphene-loaded epoxy and graphene-loaded polyvinyl alcohol films and nanofibers; these composites consistently show enhanced modulus, strength, and electrical conductivity. We also demonstrate novel results in the area of graphene aerogel templating to achieve an ultralow percolation threshold. These dispersions also show promise for applications to organic solar cells, conductive films, and inkjet-printed electronic devices.

Non-covalent functionalization, dispersion, and processing of colloidal graphene

247th National Meeting (2014)

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