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ION EFFECTS ON SELF-HEALING POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID) GELS

Ling, Zichen
http://rave.ohiolink.edu/etdc/view?acc_num=akron1556767022932537

Abstract Details

2019, Master of Science, University of Akron, Polymer Engineering.
It has long been known that polyelectrolyte-based ionotropic hydrogels can be formed via electrostatic interaction between polyanions and multivalent cations. Because of the dynamic nature of electrostatic interaction, the broken network of ionotropic gels can be recovered under certain conditions, allowing high chain mobility. The formation of ionotropic gel using polyelectrolytes and salts is a complicated process, since various factors can impact this process, such as electrostatic interaction, configuration of polymer chains, the binding mode of ions with polyelectrolytes, as well as the presence of water in the network. In this study, the complexation process of Poly(acrylic acid) (PAA) or Poly(methacrylic acid) PMAA with three different divalent salts, including CaCl2, BaCl2, and MgCl2, was systematic studied, for the purpose of synthesizing ionotropic gels. Specifically, the mixing of PMAA with CaCl2 or BaCl2 and the mixing of PAA with CaCl2 leads to the formation of gel-like complexes, while mixing of PMAA or PAA with MgCl2 results in the formation of viscous liquid-like complexes and mixing of PAA with BaCl2 gives rise to flocculent precipitates. The mechanical and self-healing properties of both the gel-like complexes and viscous liquid-like complexes were investigated using dynamic rheological measurements. Fourier transform infrared spectroscopy (FTIR) spectroscopy was utilized to study the binding modes of divalent ions with polyelectrolytes. Isothermal titration calorimetry (ITC) was used to demonstrate the association process of divalent ions with polyelectrolytes, which is a multiple-step process, first is the electrostatic interaction between divalent ions and polyelectrolytes, the other is the phase separation. Thermal gravimetric analysis (TGA) and Calcium electrode were used to determine the salt content in the polyelectrolyte/salt complexes and measure the concentration of Ca2+ in the gel complexes. Water content in the gel complexes also was measured to explore the factor to influence the properties of polyelectrolyte/salt complexes. The result shows that different concentration of salt solution creates different osmotic pressure, the amount of water in the complexes changes accordingly, so the concentration of divalent ions in the gel complexes may be different. This is a possible factor to influence the rheological behavior and self-healing properties in the different molar ratio gel complexes. Difference in the type of salts and polyelectrolytes has a strong impact on the mechanical and self-healing properties of the prepared complexes. Among all the complexes studied here, PMAA/BaCl2 gel complexes show the highest storage and loss moduli as well as the best self-healing properties. This is may because the higher binding efficiency of Ba2+ than Ca2+ which was determined by ITC data.
Nicole Zacharia (Advisor)
Bryan Vogt (Committee Member)
Kevin Cavicchi (Committee Member)
Yu Zhu (Committee Member)
67 p.
Polymer Chemistry; Polymers

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Citations

  • Ling, Z. (2019). ION EFFECTS ON SELF-HEALING POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID) GELS [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1556767022932537

    APA Style (7th edition)

  • Ling, Zichen. ION EFFECTS ON SELF-HEALING POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID) GELS. 2019. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1556767022932537.

    MLA Style (8th edition)

  • Ling, Zichen. "ION EFFECTS ON SELF-HEALING POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID) GELS." Master's thesis, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1556767022932537

    Chicago Manual of Style (17th edition)

akron1556767022932537
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© 2019, some rights reserved.Creative Commons License ION EFFECTS ON SELF-HEALING POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID) GELS by Zichen Ling is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Akron and OhioLINK.