Degree
Doctor of Philosophy (PhD)
Department
Chemical Engineering
Document Type
Dissertation
Abstract
Bottlebrush polymers, a type of non-linear polymer characterized by densely grafted side chains on a linear backbone, offer a versatile platform for material design due to their unique thermomechanical and rheological behavior. Addressing the grand challenge of achieving structural precision for bottlebrush polymers remains crucial because traditional disperse mixtures are plagued with batch variability, limiting our ability to control their functions, and correlate theoretical predictions with experiments. To date, narrow-dispersity bottlebrush polymers remain highly heterogeneous, as they are typically synthesized from disperse linear building blocks.
To address this longstanding challenge of structural heterogeneity in brush polymers, the primary objective of my doctoral research is to elucidate the structure-property relationship of brush polymers, i.e. what are their design rules? – through the synthesis and characterization of topologically precise and discrete bottlebrush polymers. By developing strategies to synthesize such molecularly precise non-linear polymers (discrete, Đ = 1.0) for the first time, I demonstrated the importance of structural precision in polymers for structure-property relationships and theoretical studies. Ultimately, having established the roles of each structural parameter in governing the overall properties of bottlebrush polymers, I explored their potential as new biomaterials for transforming additive and sensing/diagnostic/healthcare technologies. Chapter 1 introduces key concepts that describe the structure and conformation of bottlebrush polymers and then highlights the role of dispersity in the properties of linear polymers that form their building blocks.
Chapters 2 and 3 describe a versatile strategy for isolating discrete macromonomers (bottlebrush precursors) and polymerizing them into precision bottlebrush structures. We identify the length-dependent polymerization kinetics which influence the topology of conventional disperse bottlebrush polymers. We demonstrate the impact of precision on the interaction of bottlebrush polymers at an interface. Chapter 4 outlines versatile strategies for tailoring the glass transition temperature (Tg) of bottlebrush polymers by leveraging structural precision.
In chapters 5 and 6, we access fully discrete functional bottlebrushes and leverage them for technological applications, including water-soluble MRI contrast agents for disease diagnosis. In summary, this work represents a significant advancement in synthetic polymer chemistry and engineering, particularly in overcoming the challenge of structural heterogeneity in bottlebrush polymers.
Date
11-1-2024
Recommended Citation
Ogbonna, Nduka D., "Precision Bottlebrush Polymers: Synthesis, Characterization, and Structure-Property Relationship" (2024). LSU Doctoral Dissertations. 6634.
https://repository.lsu.edu/gradschool_dissertations/6634
Committee Chair
Lawrence, Jimmy