Project Director

Barbee, Meredith

Department Examiner

Pienkos, Jared; Yang, Wang-Yong, 1974-

Department

Dept. of Chemistry and Physics

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Hydrogel materials, which are polymer networks comprised mostly of water, hold significant promise for biomedical applications due to their compatibility with biological systems. Conventional hydrogel materials are often brittle and weak, but most applications in biomedical systems require materials to be strong and tough. The topology of a polymer network dictates its mechanical properties. An important strategy for designing tougher hydrogels is the release of stored length, such as from the unfolding of polyprotein cross-linkers. Inspired by the success of the strategy, we report progress towards a fully synthetic design using single chain nanoparticles (SCNPs) into a hydrogel. SCNPs, which have been widely studied for their protein mimetic functions, have shown to store and release stored length under mechanical force or in response to a stimulus in solution. We hypothesize that SCNPs can be incorporated into a polymer network to provide a strengthening mechanism due upon unfolding. Our strategy is to prepare SCNPs through reversible addition-fragmentation chain-transfer (RAFT) polymerization using bifunctional chain-transfer agents, and reinitiating polymerization to synthesize networks from the chain ends. We report on successful synthesis of bifunctional chain-transfer agents, synthesis of macromolecular chain-transfer agents (macro-CTA), reinitation of RAFT polymerization to elongate polymer chains, and synthesis of polymer networks through reinitiating RAFT polymerization. In the future, following this methodology SCNP macro-CTA will be synthesized and incorporated into a hydrogel network material via the reinitiation of RAFT polymerization.

Acknowledgments

I would like to thank Dr. Barbee. I am so fortunate to have an advisor who allows for me to think things out on my own but is always there when I need help and guidance during my research. Her allowing for me to pursue my own hypothesis has helped me realize how much I enjoy doing research and has helped me realize that I would like to pursue a career in polymer chemistry research. She has celebrated my successes, and she has been there through my hardships. Through her I have learned how to do lab research safely, how to prepare presentations, and how to write scientifically. Thank you, Dr. Barbee, for everything you have done for me. I could not have asked for a better research advisor, and I think I will have a hard time finding an advisor that compares in graduate school. You have truly inspired me. I hope to someday be as strong of a leader and as knowledgeable of a researcher as you are. I would like to thank all of the undergraduate researchers from the Barbee group. First, Graham Ford who I did not get the pleasure of getting to do research with for long, but who let me shadow him the last semester of his senior year, the week before finals week. I thank you for that experience as it helped reaffirm in me that I would like to try research. Second, I would like to thank Kelly Hooper who taught me most of my size exclusion chromatography knowledge. You were such an inspiration to me in everything I did in the research lab. Thank you for being an amazing research partner and a great friend. Third, I would like to thank Sam Robinson who has written his thesis and applied to graduate schools alongside me. I thank you for your support in research, in classes, and as a good friend. Finally, I would like to thank Lillie Poarch, Pryce Bevins, Neel Patel, Mattie Purcell, Christine Rukeyser, and Abigail Hurst. Thank you all for your friendship and support in research and classes throughout my time at UTC. I would like to thank Dr. Pienkos and Dr. Yang for being on my thesis committee. I thank the both of you for your guidance and support as I have written my thesis and progressed through my senior year at UTC. I would also like to thank Dr. Amrhein, Dr. Jennings, Professor Alonge, and Dr. Stein who have all been great mentors to turn to as I have worked on my thesis and my undergraduate degree. I thank you all for your kindness, your support, and for letting me yap. I would like to thank the UTC Chemistry and Physics department for all the opportunities and resources that have been provided for me during my undergraduate degree, including the Summer Undergraduate Research Program and the Grote Research Fund. I would also like to thank the Center of Excellence in Applied Computational Science and Engineering and the Dr. Kyle Knight Research fund for providing the funding that helped make this research possible. Finally, I would like to thank my friends and family for always being there for me through it all. I thank all of you for being there, for being someone to call, for the support, and for the practice presentations. I could not have made it this far without you all.

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

Colloids; Polymer networks; Polymerization; Polymer solutions

Keyword

single chain polymer nanoparticle; RAFT polymerization; hydrogel; reinitiation; bifunctional CTA

Discipline

Polymer Chemistry

Document Type

Theses

Extent

iii, 45 leaves

DCMI Type

Text

Language

English

Rights

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

License

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

Download

Share

COinS