Madeline Buxton
Advisor: Prof. Vladimir V. Tsukruk

will defend a doctoral thesis entitled,

Engineering and Nanoscale Characterization of Two-Dimensional Complex Interfaces in Heterostructure Assemblies

On

Monday, July 14 at 9:30 a.m.
MoSE Room 3201A
and/or
Virtually via Zoom

Committee
           Prof. Vladimir Tsukruk – School of MSE (advisor)
     Prof. Kyriaki Kalaitzidou, School of ME, MSE
      Prof. Shucong Li, School of MSE
       Dr. Dhriti Nepal, Air Force Research Laboratory
      Prof. Meisha Shofner, School of MSE

Abstract
The development of next-generation nanocomposites hinges on the ability to design novel low-dimensional systems while understanding the fundamental material properties that govern their performance. These materials often exhibit pronounced chemical, morphological, and mechanical heterogeneity at the nanoscale which critically influences bulk behavior but remains poorly understood with only the use of conventional, bulk-averaging characterization techniques.
This work quantifies surface properties of two dimensional (2D) materials, specifically graphene oxide and MXene through newly developed and validated analytical techniques. We reveal the effects of molecular functionalization-dependent variables via the fabrication of monolayers of modified nanoflakes. Both 2D material species exhibit nanoscale heterogeneity of their surface potential, stiffness, and chemical bonding. This is evident particularly at flake edges, defects, and boundaries, which govern the macroscopic behavior of 2D nanoflake films, as the surface-dominated nature of low-dimensional materials causes interfacial and defect-driven effects to eclipse conventional bulk behavior. Next, we investigate their performance in engineered heterostructures through the fabrication of films composed of cellulose nanocrystals (CNCs) and MXene. These hybrid films exhibit high optical transparency and well-defined structural color with minimal bilayer thickness, enabled by nanoscale control over periodicity. Observed optical behavior shows high sensitivity to interfacial morphology and thickness, underscoring the critical role of structural alignment in layered nanocomposites. To fully characterize such nanoscale interfacial phenomena, Nano-IR spectroscopy techniques specific to complex, low IR responsive materials are developed and validated as a tool to spatially resolve nanoscale domain-specific vibrational signatures.
In summary, this dissertation establishes foundational insight into the chemical, mechanical, and optical behavior of low-dimensional materials, from single-nanoflake resolution to assembled thin-film structures. As demand grows for biocompatible, adaptable, and multifunctional materials, this work establishes a framework for leveraging nanoscale morphology and chemistry to engineer next-generation heterostructures with precision and predictability.