Interest in 2-D nanomaterials has increased dramatically since the discovery of graphene and as such, research in the field has significantly expanded in the last decade. Graphene oxide (GO) has been of particular interest for many reasons, including the ease and scalability of synthesis and its simple route to reduced graphene oxide. There is tremendous interest in the development of ultrathin graphene and graphene oxide films as molecular transport barriers, or as selective membranes that use molecular sieving properties for small molecular separation or recovery technologies. Graphene oxide films in particular, have been shown to be excellent barriers to the transport of small-molecule gases in the dry state, but expand in the presence of water vapor to allow rapid permeation of H<sub>2</sub>O through nanochannels created in the intersheet gallery spaces. Here we explore a new application for GO films as water-breathable barriers for chemical protection of personnel that allow outward perspiration while protecting the wearer from the back diffusion of chemical toxicants or biochemical agents. The interlayer channels in GO films are sufficiently small to exclude larger chemical and biochemical toxicants, but some toxicants are small molecules that can fit in the &lt; 1nm transport channels, and are known to be co-transported with water. Here we present a theoretical model of small-molecule toxicant diffusion in GO films with motion inward against an outward flow of water to identify conditions where both perspiration and environmental protection can co-exist. We have developed an experimental facility suitable for study of vapor permeation in both directions simultaneously, and show results for two model small-molecule vapor agents. Ethanol and trichloroethylene (TCE) were chosen as models due to their widely varying solubility in water. The results point to design parameters (film thickness, toxicant properties) that allow both outward water transport and the results suggest that GO can indeed be used to create breathable toxicant barriers as components in wearable devices for chemical and biochemical detection.

Breathable graphene oxide toxicant barriers

253rd National Meeting (2017)

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