(309c) Award Submission: Molecular Barrier Functions of Graphene Oxide in Liquid-Liquid Systems

Graphene oxide (GO) is an effective stabilizer for a range of organic-in-water emulsions. The high stability of GO-based emulsions is due to in part to the formation of robust multilayers at the interface that effectively cover the droplet surface, allowing for full passivation of droplet surface patches left uncovered by packing inefficiencies in the first monolayer.  In this work, we show that these GO interfacial films demonstrate unique molecular barrier properties at the liquid− liquid interface, a phenomena that is not observed when non-platelike stabilizers are used.  These films are able to inhibit transport from the droplet interior and cause a significant suppression of dispersed-phase evaporation rates with potential applications in controlled release.  They are also able to protect the dispersed phase from attack by reactive oxygen species, which typically react at diffusion-limited rates.  The mechanism for protection is hypothesized to be a combination of hydroxyl radical scavenging and creation of tortuous pathlengths that hinder diffusion to the interior phase.