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KChen PhD Dissertation.pdf (10.16 MB)

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Roll-to-Roll Manufacturing and Real-Time Characterization of Bio-Functional Polymers

Chen, Keke
http://rave.ohiolink.edu/etdc/view?acc_num=akron1548177736839976

Abstract Details

2019, Doctor of Philosophy, University of Akron, Polymer Engineering.
Polymeric materials have been used in the healthcare and medical industry for decades, with advantages from design flexibility to cost-effective manufacturing. Despite the wide adoption of polymeric materials in the field, challenges remain, including i) the capability to integrate a roll-to-roll (R2R) process to fabricate bio-functional devices and ii) the ability to harness and understand the properties associated with any mechanical or thermal history during device fabrication. The research herein focuses on fundamental molecular-level understanding of the structure development of bio-functional polymers during mechanical and thermal processes, and continuous R2R processes for post-functionalization with surface attached bio-functionalities. The first part of the research utilizes a real-time birefringence measurement system to study the stress-optical relationships a series of α-Amino acid-based poly(ester urea)s (PEUs). PEUs are a new class of materials that have shown promise for biomedical applications due to their biodegradability, biocompatibility and enhanced mechanical properties. The hydrogen bonding species associated with the urea groups in the structure provides a nonchemical method to strengthen their physical properties and to impart unique performance characteristics including shape memory properties. The molecular structure evolution of PEUs during a complex shape memory cycle was studied by real time mechano-optical, Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray scattering (WAXS) measurements over a range of temperatures. A characteristic temperature, defined as the liquid–liquid (Tll) transition (rubbery–viscous transition), was found at about 1.05 Tg (K) (at Tg + 15 °C), at which temperature the mean relaxation time and shape recovery ratio for the polymer were also maximized. The hydrogen bonding strengthened supramolecular packing, the rearrangement of which associated with the deformation history was revealed to ultimately determine the shape memory properties of PEUs. Bridging the gap between lab-scale research and scaled-up production, the second part presents a continuous roll-to-roll (R2R) fabrication of antimicrobial fiber mats with surface attached quaternary ammonium compounds (QACs) as contact-killing antimicrobials. The entire process was achieved using a customized R2R manufacturing platform that combines a multi-nozzle electrospinning technique to generate homogeneous fiber mats, and a dipping cycle with UV treatment for post-functionalization. A facile thiol-ene “click” reaction was used to chemically tether a QAC thiol (QAC-SH) on the surface of electrospun fibers containing an alkene functional handle (allyl-TPU). The control of electrospinning condition and electrospun fiber morphology was investigated by changing the solution concentrations and the tip-to-collector distance (TD). Surface functionalization was assessed by fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS) for the covalently attached thiol quantities following the “click” reactions. Antimicrobial assay results demonstrated the fast (> 45% in 30 min) and long-term (1 – 3-log reduction in 4 h and 24 h) contact-killing efficacies of QAC-SH functionalized fiber mats against both Gram-positive (S.aureus) and Gram-negative (E.coli) bacteria, further proving the feasibility of implementing the post-functionalization process in a continuous R2R manner.
Matthew Becker (Advisor)
Mukerrem Cakmak (Advisor)
Nicole Zacharia (Advisor)
Younjin Min (Committee Chair)
Rebecca Willits (Committee Member)
219 p.
Engineering; Materials Science; Polymers
Roll-to-roll; real-time characterization; electrospinning; post-fabrication; surface functionalization; birefringence; stress optical behavior; hydrogen bonding; antimicrobial; quaternary ammonium compound; contact-killing

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Citations

  • Chen, K. (2019). Roll-to-Roll Manufacturing and Real-Time Characterization of Bio-Functional Polymers [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1548177736839976

    APA Style (7th edition)

  • Chen, Keke. Roll-to-Roll Manufacturing and Real-Time Characterization of Bio-Functional Polymers. 2019. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1548177736839976.

    MLA Style (8th edition)

  • Chen, Keke. "Roll-to-Roll Manufacturing and Real-Time Characterization of Bio-Functional Polymers." Doctoral dissertation, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1548177736839976

    Chicago Manual of Style (17th edition)

akron1548177736839976
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