M.A. Creighton, W. Zhu, F. Van Krieken, R.A. Petteruti, H. Gao, R.H. Hurt
Keywords: graphene oxide, barrier, self assembly, emulsion
Summary:Multi-layer films made of graphene and related materials are of great interest as high-performance molecular barriers; though much research is focused on planar laminate films. Graphene and graphene oxide (GO) sheets are also known to spontaneously self-assemble at liquid-liquid interfaces on the surfaces of dispersed droplets, but much less is known about the barrier properties of these ultrathin films in 3D curved micro-geometries. This article demonstrates that such 3D self-assembled graphene films at liquid-liquid interfaces can be used to control molecular transport and reactions between droplet and continuous phases. We show that this previously unappreciated effect can be exploited to control the release of small molecules from dispersed liquid phase droplets. Examples covered include tunable release rates of volatile compounds, effective inhibition of undesirable interfacial chemical reaction processes such as oxidative attack, which is an undesirable pathway implicated in many chemical product degradation and spoilage processes. In some cases, the local barrier function is so effective that it is uniquely able to kinetically inhibit mixing, resulting in novel, never before seen emulsion phases consisting of two fully miscible but segregated liquids.