Graphene has recently gained considerable interest as a filler for composite materials because of its intrinsic mechanical, thermal, and electrical properties. Its lack of solubility in virtually all solvents has led to the common practice of either using graphene oxide or reduced graphene oxide in the place of pristine graphene sheets. Both of these graphene derivatives, however, have significantly reduced properties when compared to the pristine material. Here, instead of viewing the insolubility of pristine graphene as an obstacle to be overcome, we utilize it as the means to create oil/water emulsions, with graphene acting as a surfactant to stabilize the spheres. These emulsions are then used as the framework to make a wide variety of foam composites. This is a fundamentally new approach, as it does not require chemical functionalization, surfactants, high boiling solvents, or the input of large amounts of heat or mechanical energy.<br/><br/>Our earlier work focused on using styrene to produce low density, high strength conductive foam composites. This presentation will focus on the use of a different monomer, butyl acrylate, used to produce a flexible, low-density conductive foam composite whose specific electrical resistance is a function of the highly ordered graphene network that lines the foam cells. Any variation of this network results in a drastically different resistance value. This is shown to allow the use of these composites as pressure sensors. Additionally, the foams swell to absorb large amounts of oil very quickly, altering the organized graphene network, making the foams sensitive to the presence of oil.

Pristine graphene stabilized emulsions as the basis for flexible conductive foams for oil and pressure sensing

250th National Meeting (2015)

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