Project Director

Barbee, Meredith

Department Examiner

Pienkos, Jared; Lee, John

Department

Dept. of Chemistry and Physics

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Hydrogels are a class of polymer networks that show promise in many biomedical applications but are typically limited in use due to their brittle nature. Synthesizing hydrogel networks that are comparable to biological materials has long been an area of interest. In this study, we are working to create a polymer network inspired by the muscular protein, titin. Titin can unfold under mechanical tension, releasing stored length, making the muscle material extensible and durable. To mimic this behavior, we propose creating a polymer network with similar stored length using single chain nanoparticles (SCNPs) cross-linked with phenolphthalein (PP) and β-cyclodextrin (β-CD). We hypothesize that the polymer chains will fold due to the hydrophobic host-guest interaction between the two molecules, resulting in an SCNP. These SCNP will be used as the crosslink in a polymer network, and when mechanical force is applied, we hypothesize the interactions between PP and β-CD will break, unfolding the SCNP and mimicking the titin protein. Here we report the successful synthesis of acrylamide (Aam) PP and β-CD monomers for use in polymerization reactions. We also report on attempts to demonstrate a mechanochromic nature of the PP-β-CD complex, including the synthesis of various concentrations of both single-network and double-network hydrogels and attempts to control the rate of association of the PP-β-CD complex via the use of a competitive guest. Finally, we report on the successful synthesis of various single polymer chains using reversible addition-fragmentation chain-transfer (RAFT) polymerization, including the precursor polymer to be used as the SCNP crosslinker. Future work will include the further characterization of the SCNP precursor polymer, the optimization of the polymerization reaction, and the integration of the SCNP as a crosslinker in a hydrogel network. Subsequent mechanical testing of the material will indicate whether the SCNP hydrogel exhibits mechanical properties comparable to that of the titin protein.

Acknowledgments

I want to thank Dr. Meredith Barbee for three fantastic years of research. I would not be where I am today if it were not for your kindness and support through even some of my most difficult times. Thank you to my lab mates in the Barbee research group: Kelly Hooper, Graham Ford, and Dallas Donovan. Research can be tough, but all the laughs and ideas we provided one another helped to make the lab a place I enjoyed even more. I want to thank all the faculty of the UTC Chemistry Department for helping to mold me into the scientist I am today. I want to thank all sources that helped to fund my research: the UTC Grote Scholarship and Research Fund, the Dr. Kyle Knight Chemistry Research Fund, and the Center of Excellence for Applied Computational Science and Engineering. I am also very grateful to my friends and family for their nonstop support through the difficulties of college.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2025

Subject

Biomimetics; Colloids; Polymer networks; Polymerization; Polymer solutions

Keyword

hydrogel; biomimetic design; RAFT; material strength

Discipline

Polymer Chemistry

Document Type

Theses

Extent

iii, 66 leaves

DCMI Type

Text

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by-nc-nd/4.0/

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