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Exploiting Protein- and Synthetic Polymer-Based Materials for Use in Tunable Biological Mimics and Devices

Walker, Anne
http://rave.ohiolink.edu/etdc/view?acc_num=case1554508268871554

Abstract Details

2019, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Poly(acrylic acid) (PAA) is an anionic polyelectrolyte that sees a number of commercial uses, chiefly to exploit crosslinked PAA’s superabsorbance. These materials tend to be soft and brittle with low elasticity. In contrast, we have found that PAA hydrogels synthesized with high concentrations of salt exhibit properties markedly different from both PAA hydrogels synthesized without salt and those incubated in the same amount of salt post-synthesis. Examples of these changes include reduced equilibrium swelling, substantially increased elongation, increased modulus, and near-complete recovery after strain. Investigated salts include chloride salts of lithium, sodium, cesium, calcium, and zinc. The greatest enhancement in viscoelastic behavior comes from multivalent salts such as zinc chloride, but is also evident in lithium chloride-loaded samples. The enhanced mechanical properties of these salt-loaded gels significantly diminish upon washing the materials with water to remove the salt, and cannot be restored upon incubation in solutions containing equivalent concentrations of salt. This indicates that the presence and organization of the salt during synthesis is critical to the property changes. Furthermore, the inability of the materials to regain these mechanical properties by soaking them in salt solutions preclude simple explanations for enhancement, such as the chelation of multivalent ions leading to ionic crosslink formation. This fundamental study led to a strong curiosity into poly(acrylic acid) product design. Initially, the primary end-use envisioned for these gels was as a mimic for biological materials such as nerve and muscle tissue, which are essentially complex cation exchange membranes. Understanding the role and organization of the metal in these high-salt PAA gels gave insight into structuring an investigation of said tissue mimics. This then sparked interest in using each layer of knowledge that had been gathered to develop a suite of poly(acrylic acid) materials, using an iterative design scheme to streamline this process. In the end, the marriage of very fundamental science with application-centric product development allowed for the creation of a suite of products, of which three will be discussed in this dissertation. This iterative design process has since been applied to projects outside of poly(acrylic acid), and still yields successful rapid product development.
Gary Wnek (Committee Chair)
Michael Hore (Committee Member)
Horst von Recum (Committee Member)
David Schiraldi (Committee Member)
189 p.
Biomedical Engineering; Materials Science; Polymers
polyelectrolyte, hydrogel, gel, viscoelasticity, network, hemostat, silk, aerogel, prosthetics, organophosphorus toxins,

Recommended Citations

Citations

  • Walker, A. (2019). Exploiting Protein- and Synthetic Polymer-Based Materials for Use in Tunable Biological Mimics and Devices [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1554508268871554

    APA Style (7th edition)

  • Walker, Anne. Exploiting Protein- and Synthetic Polymer-Based Materials for Use in Tunable Biological Mimics and Devices. 2019. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1554508268871554.

    MLA Style (8th edition)

  • Walker, Anne. "Exploiting Protein- and Synthetic Polymer-Based Materials for Use in Tunable Biological Mimics and Devices." Doctoral dissertation, Case Western Reserve University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554508268871554

    Chicago Manual of Style (17th edition)

case1554508268871554
225
© 2019, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.