(24i) Dynamics and Morphological Evolution of Graphene and Graphite Films at Fluid-Fluid Interfaces

Fluid-fluid interfaces can be used as construction sites to assemble graphene sheets into films for applications in which transparency and electrical conductivity are vital, such as in optoelectronics. Several groups have shown that graphene and other 2D materials form thermodynamically-favorable films at fluid-fluid interfaces, but the dynamics of how these films form are still poorly understood. While lateral interactions are common for materials pinned to a fluid interface, platelet-like particles can also partake in stacking and unstacking events, which are critical to understand for 2D materials with layer-dependent properties. Thus, understanding how the dynamics of graphene at fluid interfaces govern film morphology will allow for the creation of films with the desired transparency, conductivity, or other film properties desired for a given application. Through dynamic and quiescent measurement techniques in a Langmuir trough, coupled with in situ and post-deposition analysis of interfacial structure, one can begin to investigate the competing interactions at different fluid-fluid interfaces that govern the dynamics and interfacial structure of graphitic films. We will present results from our investigations of the interfacial dynamics of graphene and graphite at both the air-water and oil-water interfaces and discuss how the dynamics affect interfacial morphology.