Collaborative Research: Linking Structure with Transport in Graphene-Based Films at Fluid-Fluid Interfaces

Small particles are ubiquitous in nature and many times they can sit on the surface of liquids, such as water, or between two liquids, such as when oil and water meet. These particles then impact how molecules move between the air and the water, or the oil and the water, and thus influence many natural processes. This collaborative project will help answer important questions about how sheet-like particles organize on the surface of liquids, and how the organization alters the movement of molecules from a gas to a liquid, or a liquid to a liquid.

This knowledge is important for creating materials for sustainable foods, pharmaceuticals, and coatings, and for helping to design and build better particles. The proposed work involves two research groups, one in chemical engineering at Colorado School of Mines, and one in materials science and engineering and chemistry at Texas A&M. Undergraduate and graduate students from both institutions will share knowledge across the different disciplines while they perform research. They will gain the foundational skills required to be leading scientists in the STEM workforce.

The goal of this project is to understand the relationship between the structure of 2D particle films at fluid-fluid interfaces and the mass transport across the films. Preliminary work indicates a complex and unknown relationship between particle area concentration and permeability, and microscopy data reveal that 2D particles form heterogenous films with structure that depends on area coverage and particle oxidation.

The central hypothesis is that permeability across 2D particle films will be governed either by film heterogeneity or tortuosity depending on particle area concentration. The researchers will probe this hypothesis by combining theoretical transport models with experiments visualizing graphene oxide (GO) film structure and experiments quantifying interphase mass transport.

This collaborative work leverages expertise in fabricating particles and organizing nanosheets at interfaces, as well as development of an array of techniques for visualizing 2D particle film structure at fluid-fluid interfaces with microscopy. The PIs will support the development of undergraduate and graduate student researchers and will jointly develop and implement a half-day workshop on particles at interfaces to be held in association with the ACS Colloid & Surface Science Symposium.

Graduate students will be trained in laboratory skills, critical thinking, data analysis, and dissemination of research results, and they will participate in joint meetings between lab groups to facilitate the exchange of knowledge and expertise.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.