(363i) Fabrication and Investigation of Shape-Controlled Tri-Layer Graphene Particles at Fluid-Fluid Interfaces

Two-dimensional (2D) materials, including graphene, are a class of highly anisotropic particles due to thicknesses on the nanometer or sub-nanometer scale, and lateral sizes that can range up to millimeter in scale. There is growing literature surrounding the scalable assembly and deposition of these materials from fluid-fluid interfaces for uses in next-generation, thin-film devices, but our lack of understanding of the lateral (in-plane) interactions between 2D particles at fluid-fluid interfaces is an impediment to rapid progress in this area. Since film properties depend on the assembled film morphology, which itself is a product of particle-particle interactions, it is desirable to understand the forces that drive self-assembly between 2D materials at fluid-fluid interfaces. There is evidence that weak capillary interactions play a significant role in such assembly behavior, but capillary interactions have not been directly observed or quantified in these systems. In this work we seek to use lithographic methods to fabricate size- and shape-controlled tri-layer graphene, transfer it to an air-water interface, and observe both self-assembly behavior and evidence of capillary interactions with a combination of microscopy techniques and gel trapping. We will present the process for creating these particles and transferring them from the growth substrate, describe our observations of individual particles and particle assemblies, and discuss the consequences for our understanding of inter-particle interactions in these systems.