Design, synthesis, and applications of architecturally engineered polymers
Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Chemical and Environmental Engineering (ENAS)
First Advisor
Zhong, Mingjiang
Abstract
The form of intramolecular connections in polymer chains dictates their ensemble properties. Non-linear polymers exhibiting graft, cyclic, dendritic, and randomly branched topologies offered a versatile material design platform, enabling the adjustment of thermomechanical behaviors, fine-tuning of functional group density, and incorporation of diverse functionalities. This polymer architecture engineering strategy, complementary to linear polymer design, paves the way for a myriad of practical applications. This thesis contributes to this field by developing two innovative polymer architectures derived from graft (co)polymers, aiming to expand the range of synthetically accessible polymer structures, deepen the understanding of their structure–property relationships, and unlock new frontiers in materials science. The first part of the thesis presents the development of multicomponent mixed-graft block copolymers (mGBCPs), which incorporate a variety of side chain polymers covalently bonded to a linear backbone in a sequence-defined manner. The self-assembly of mGBCPs gave rise to a series of hierarchical phase-in-phase morphologies with independently tunable lattice parameters, facilitating the exploration of complex morphologies and demonstrating their potential for multifunctional material design. Building upon this foundation, the research extends to the coassembly of mGBCPs with inorganic fillers, leveraging the specific interactions between side chains and nanofillers. This approach enabled the controlled integration of various nanofillers into the target domains of the polymer matrix, creating nanocomposites characterized by well-defined inter-filler distances and arrangements, thereby expanding the potential applications of mGBCPs in the field of nanomaterials. The subsequent part of this thesis explores the brush-on-brush polyelectrolytes, where the linear side chains in traditional graft polymers were replaced by biomimetic anionic bottlebrush copolymers. This hierarchically branched structure is synthesized using a combination of grafting-to and grafting-from techniques, allowing for precise control over key structural parameters, including the degrees of polymerization of backbones, primary and secondary side chains, as well as the grafting densities of primary and secondary side chains. We anticipate that this bioinspired architecture design could emulate the tribological and mechanical properties of aggrecan aggregates in natural cartilage and advance the development of biomedical materials for cartilage replacement.
Recommended Citation
Xue, Yazhen, "Design, synthesis, and applications of architecturally engineered polymers" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1307.
https://elischolar.library.yale.edu/gsas_dissertations/1307
