Author ORCID Identifier
https://orcid.org/0000-0002-0746-7397
Date of Award
Fall 11-14-2025
Document Type
Thesis (Ph.D.)
Department or Program
Chemistry
First Advisor
Wenlin Zhang
Second Advisor
Chenfeng Ke
Abstract
Designing organic materials with precisely controlled functions remains a central challenge in chemistry and materials science. Two important classes of organic materials are polymer networks and crystalline frameworks. Although they exhibit fundamentally different morphologies and synthesis routes, they share some structural principles that govern their behaviors. This thesis explores two of these key principles: crystallinity and topology, and their roles in controlling structure–property relationships.
To address the challenge of achieving high crystallinity in stable organic frameworks, we developed a synthetic strategy to construct hydrogen-bonded crosslinked organic frameworks (H\textsubscript{C}OFs). These materials are formed by assembly of hydrogen-bonding motifs followed by single-crystal-to-single-crystal covalent crosslinking, enabling the combination of large pores, enhanced stability, and high single-crystallinity. The unique topology formed by hydrogen bonding and covalent crosslinking endows the resulting frameworks with the abililty to retain long-range order during guest-induced expansion/contraction. This work in Chapter 2 establishes a platform for creating dynamic crystalline frameworks with tunable porosity and robustness.
Crystallinity and topology in polymer systems were investigated through the lens of entanglements and interfacial compatibilization. Using coarse-grained molecular dynamics simulations, we examined how interfacial incompatibility and block copolymer compatibilizers affect crystallization and mechanical response (Chapters 3–4). The results show that entanglement density and chain architecture play decisive roles in determining stress transmission and interfacial strength, while block copolymers can modulate both local crystallinity and failure mechanisms by bridging interfaces and introducing topological constraints.
Finally, we initiated the development of a united-atom simulation framework to model the crystallization of recyclable, polyethylene-mimic aliphatic polyesters (Chapter 5). Preliminary studies reveal the relationship between layer packing and chain architecture, suggesting a direct link between molecular structure and mesoscale ordering. Ongoing work aims to establish structure–property correlations for these sustainable semicrystalline polymers.
Together, these studies demonstrate that crystallinity and topology are unifying design principles for both organic frameworks and polymer networks. By demonstrating how molecular packing and connectivity control structure and dynamics across these systems, this thesis provides insight that may inform the rational design of multifunctional organic materials.
Original Citation
Samanta J, Zhang Y, Zhang M, Chen, A. Ke, C. Single-crystalline hydrogen-bonded crosslinked organic frameworks and their dynamic guest sorption. Acc. Mater. Res., 2022, 3(11): 1186-1200.
Zhang, Y.; Liang, R.; Atterberry, B.; Li, F.; Staples, R.; Zhang, J.; Samanta, J.; Rossini, A.; Ke, C.; Ultra-dynamic Isoreticularly Expanded Porous Organic Crystals J. Am. Chem. Soc. 146.22, 2024: 15525-15537
Zhang, Y.; Zhang, W.; Effects of Block Copolymer Compatibilizers and Interfacial Entanglements on Strengthening Immiscible Glassy Polymer Blends Macromolecules, 58.5 2025: 2484–2493
Recommended Citation
Zhang, Yunjia, "Crystallinity and Topology in Organic Materials: From Crystalline Frameworks to Polymer Networks" (2025). Dartmouth College Ph.D Dissertations. 439.
https://digitalcommons.dartmouth.edu/dissertations/439
