Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List

Full text release has been delayed at the author's request until October 01, 2024

ETD Abstract Container

Abstract Header

Design, Synthesis, and Self-assembly of Dendritic Rod-like Molecules with Precisely Controlled Compositions, Interactions, and Topologies

Zhang, Ruimeng
http://rave.ohiolink.edu/etdc/view?acc_num=akron157231026041301

Abstract Details

2019, Doctor of Philosophy, University of Akron, Polymer Science.
Self-assembly of different molecular building blocks provides a versatile platform to fabricate materials with desired nanostructures and macroscopic properties. A library of molecular building blocks with either a flexible conformation (e.g., dendrons and polymer coils) or a persistent molecular shape (e.g., sphere-like, disc-like, and rod-like molecules) have been extensively exploited. Among them, rigid rod-like building blocks have generated broadest interests because of their functional nature. However, in comparison to a large variety of structures that are identified in molecules composed of only flexible building blocks, self-assembled structures of most conventional molecules consisting of rod-like components (rod-like liquid crystals materials) are commonly limited to nematic or layer smectic phases, dominated by preferred parallel arrangements of rod-like components. In this dissertation, a novel “Molecular Lego” approach has been utilized to construct materials consisting of rod-like components. Firstly, a set of “clickable” monodisperse azide-functionalized oligofluorene(s) with tunable length were synthesized. This azide-functionalized oligofluorene(s) can serve as a basic building block for the modular and efficient synthesis of molecules consisting of rigid rod-like oligofluorenes via the copper-catalyzed azide-alkyne cycloaddition “click” chemistry. We then designed and synthesized a series of dendritic oligofluorene(s) capped by a tri(hydroxyl) group. It should be noted that these molecules have precisely controlled compositions, interactions, and topologies. Distinct self-assembly behavior, sensitive to the primary chemical structure, was observed. Specifically, the parallel arrangement of rod-like components is successfully broken by synergistic effects of hydrogen bonding interaction and dendritic architecture. The balance between enthalpy and entropy results in specific fan-like or cone-like molecular shapes. While the fan-shaped molecules tend to form hexagonal packing cylindrical phases, the cone-shaped molecules can form various spherical motifs to pack into ordered structures, including the body-centered cubic, Frank-Kasper A15, Frank-Kasper σ, and dodecagonal quasicrystal phases. The formation mechanisms of complex Frank-Kasper phases were systematically investigated. This study provides a model system to engineer diverse supramolecular structures by self-assembly of molecules consisting of rod-like components and sheds new light into the formation mechanisms of unconventional spherical packing structures in soft matter.
Stephen Z.D. Cheng, PhD (Advisor)
Tianbo Liu, PhD (Committee Chair)
Yu Zhu, PhD (Committee Member)
Toshikazu Miyoshi, PhD (Committee Member)
Chrys Wesdemiotis, PhD (Committee Member)
191 p.
Chemistry; Materials Science; Polymer Chemistry; Polymers
Self-assembly; Supramolecular Structure; Frank-Kasper Phase; Rod-like Molecule; Oligo-fluorene

Recommended Citations

Citations

  • Zhang, R. (2019). Design, Synthesis, and Self-assembly of Dendritic Rod-like Molecules with Precisely Controlled Compositions, Interactions, and Topologies [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron157231026041301

    APA Style (7th edition)

  • Zhang, Ruimeng. Design, Synthesis, and Self-assembly of Dendritic Rod-like Molecules with Precisely Controlled Compositions, Interactions, and Topologies. 2019. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron157231026041301.

    MLA Style (8th edition)

  • Zhang, Ruimeng. "Design, Synthesis, and Self-assembly of Dendritic Rod-like Molecules with Precisely Controlled Compositions, Interactions, and Topologies." Doctoral dissertation, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron157231026041301

    Chicago Manual of Style (17th edition)

akron157231026041301
© 2019, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.