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Dissertation
DEVELOPMENT OF LIQUID PHASE RESONANT SOFT X-RAY SCATTERING TECHNIQUES FOR SPATIOCHEMICAL CHARACTERIZATION OF SELF-ASSEMBLED POLYMERIC NANOSTRUCTURES
Doctor of Philosophy (PhD), Washington State University
2026
Abstract
Resonant soft X-ray scattering (RSoXS) has emerged as a uniquely powerful method for probing nanoscale morphology in organic soft materials, but its application to liquid-phase systems has remained limited due to experimental and analytical challenges. This dissertation presents the development, validation, and application of liquid-phase RSoXS (LP-RSoXS), a technique that enables in-situ, chemically selective characterization of polymer self-assembly under native solution conditions. New microfluidic flow-cell architectures were designed to maintain vacuum compatibility while providing stable, controllable liquid environments, and a complete data-reduction and modeling framework was established to correct for geometric distortions and membrane deformation induced background contributions.Building on the theoretical foundations of resonant scattering, this work introduces a multi-energy spectral analysis strategy that combines contrast tuning with form- and structure-factor modeling to extract hierarchical structural information with chemical specificity. The framework incorporates polydispersity, multi-phase refractive-index decomposition, and physically constrained global fitting, enabling quantitative reconstruction of nanoparticle substructures that are inaccessible to SAXS, SANS, or optical methods.
These developments are applied to three scientifically and technologically important systems. First, flow-cell optimization studies quantifying silicon nitride (SiN) membrane deformation under pressure and identifying design rules that maximize signal throughput. Second, pH-responsive block-copolymer micelles are examined in situ, revealing previously unresolvable hydration, density, and substructure transitions driven by acid–base ionization and Donnan-mediated osmotic pressure. Third, concentration- and molecular-weight-dependent micellization in a statistical copolymer is characterized, demonstrating the sensitivity of LP-RSoXS to weakly segregated morphologies and mixed-phase interfaces.
Together, these results establish LP-RSoXS as a robust and chemically selective tool for studying soft-matter assembly in solutions, expanding the range of accessible nanostructures and opening new opportunities in nanomedicine, responsive materials, and fundamental polymer science.
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Details
- Title
- DEVELOPMENT OF LIQUID PHASE RESONANT SOFT X-RAY SCATTERING TECHNIQUES FOR SPATIOCHEMICAL CHARACTERIZATION OF SELF-ASSEMBLED POLYMERIC NANOSTRUCTURES
- Creators
- Devin Scott Travis Grabner
- Contributors
- Brian A Collins (Advisor)Mark G Kuzyk (Committee Member)Matthew D McCluskey (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Physics and Astronomy
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 140
- Identifiers
- 99901393304701842
- Language
- English
- Resource Type
- Dissertation