Committee

Prof. Vladimir V. Tsukruk – School of MSE (advisor)

Dr. Dhriti Nepal, Air Force Research Labs

Prof. Kyriaki Kalaitzidou, School of ME

Prof. Satish Kumar, School of MSE

Prof. Meisha Shofner, School of MSE

Abstract

In-depth nanoscale characterization of low dimensional materials is critical for fundamental understanding of interfacial mechanics in composite arrangements. Two-dimensional (2D) materials are of interest because of their vast applicability for varied composite and heterostructure arrangements to improve mechanical and electrical properties and add additional functionality. Among those, MXene nanoflakes and graphene, and its derivatives, provide strength, conductivity, and surface variability to composite and heterostructure materials. Heterostructure materials are attractive for their improved composite properties while maintaining a low form factor. Creating tunable heterostructures with durable interphase regions is important for a variety of applications from energy storage to EMI shielding to structural aerospace components. The wide array of possibilities for heterostructure materials makes it that much more important to have in depth understanding of the fundamental mechanisms of arrangement. Characterization of nanoscale properties is still largely in its developmental infancy and investigating localized nanoscale heterogeneity will provide valuable structure-property relationship understanding of complex composite materials.

This work aims to characterize localized phenomena of monolayer 2D materials, specifically Ti3C2Tx MXene flakes and graphene oxide, in order to fundamentally describe and be able to tailor their interfaces in complex composites. The chosen 2D materials can be engineered for controlled surface interactions while modifying composite materials. The first task of this work includes chemical surface modification of 2D flakes and characterizing distinguishability between individual flakes. The next task aims to create uniform, high surface density, controlled monolayer formation for a variety of flake chemistries. Further on, this monolayer will be extensively characterized to understand how surface chemistry affects film formation and localized mechanical, electrical and chemical properties of modified 2D materials. Next, 2D materials will be investigated at interfaces in heterostructure arrangements and within hierarchical composites to understand their functionality and be able to improve properties. Finally, building upon the knowledge gained in the previous tasks, to be considered are 2D materials and polymer resin interfaces for future applications of strong, nacre-like materials and as nanofillers in carbon fiber composite materials.

This work will facilitate the development of heterostructure materials with complex interfaces by fundamentally examining their nanoscale properties thus allowing for tunable and optimizable heterogenous materials. This is expected to be able to be applied to a variety of 2D material chemistries and expand upon the nanoscale characterization knowledge of such for potential batteries, EMI shielding, protective coating, sensing and structural electronic applications.