Morphogenesis–morphology–function relationships of irregular nanomaterials using advanced electron microscopy and graph theory

Kalutantirige, Falon Christina

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https://hdl.handle.net/2142/124698 Copy

Description

Title

Morphogenesis–morphology–function relationships of irregular nanomaterials using advanced electron microscopy and graph theory

Author(s)

Kalutantirige, Falon Christina

Issue Date

2024-04-26

Director of Research (if dissertation) or Advisor (if thesis)

Chen, Qian

Doctoral Committee Chair(s)

Chen, Qian

Committee Member(s)

• Murphy, Catherine J
• Leckband, Deborah E
• Wang, Hua
• Shen, Mei

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Electron microscopy
• Electron tomography
• Liquid-phase electron tomography
• 3D morphometry
• 3D imaging
• Polymer membranes
• Filtration
• Irregular morphology
• Anisotropy
• Structure complexity
• Graph theory
• Nanovoids

Abstract

Morphological irregularity, in the form of structural complexity, asymmetry and anisotropy, is ubiquitous in systems at all length scales. More interestingly, these irregular systems can be dynamic, showing morphological transformations with time. From the complex and irregular arrangement of celestial bodies, cosmic voids and extraterrestrial dust forming our Universe, to the size and shape of nanoparticles dictating their assemblies, morphological irregularity leads to unique properties and functions. Nanomaterials such as polymer membranes, biomaterials and nanoparticles often show three-dimensional irregular morphologies, and undergo dynamic changes in morphology. Unraveling the three-dimensional morphology in terms of formation, transformations, and functional relevance is challenging due to a lack of methodologies for imaging and quantifying these irregular nanomaterials with the needed temporal and nanometer spatial resolutions. This dissertation explores the quantitative relationships between the irregular, asymmetric and anisotropic morphology of nanomaterials, their morphogenesis mechanisms, and properties, using advanced electron microscopic techniques to capture the three-dimensional structure, coupled with quantitative morphometry and graph theory to discretize the nanoarchitecture. Firstly, the crumpled, void-containing nanomorphology of polyamide membranes is explored using three-dimensional nanostructure descriptors extracted from electron tomography at nanometer resolutions, revealing the mechanisms of nanomorphogenesis. The pore patterning and local thickness variations of the membranes uncover a Turing-like reaction diffusion instability leading to a coalescence and growth mechanism of morphogenesis. As polyamide membranes are commercially used in separation applications, local nanomorphology descriptors and graph theory are used to understand the relationship between the nanomorphology and properties. The experimental methanol permeance of polyamide membranes are theoretically modelled using nanomorphological parameters, such as local membrane thickness and nanovoid area, to provide accurate predictions of the separation properties. The irregular morphologies of polyamide membranes are quantified using three-dimensional structural skeletons from graph theory, to relate the nanomorphology to the mechanical properties in the form of the apparent modulus. Furthermore, using a volume-filled void reconstruction approach, the structural complexity of irregular and complex biological nanoparticles called brochosomes with anti-reflective and hydrophobic properties are explored. Beyond uncovering the morphology-function relationships, the evolution of morphology in bimetallic core-shell nanocubes with anisotropic etching behavior is studied using liquid-phase electron tomography. The symmetry-breaking, anisotropy evolution, and the stages of etching are revealed by structural skeleton graphs and graph theory. The dissertation highlights the interplay between morphology, emergence of structure and materials properties, to quantitatively elucidate the formation–structure–property relationships of nanomaterials.

Graduation Semester

2024-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2024 Falon Christina Kalutantirige

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