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Qiaoyun Wang Master thesis.pdf (6.21 MB)

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HYDROPHOBICALLY MODIFIED POLYELECTROLYTES TO TUNE THE PROPERTIES OF COACERVATES

Wang, Qiaoyun
http://rave.ohiolink.edu/etdc/view?acc_num=akron1590750104889183

Abstract Details

2020, Master of Science in Polymer Engineering, University of Akron, Polymer Engineering.
Association of two oppositely charged polyelectrolytes via electrostatic interaction can lead to soluble complex formation, or phase separation, including liquid-liquid (coacervation) and liquid-solid (precipitation) phase separation. Coacervation exhibits promising applications in various fields due to its unique properties. Proteins, a common polyelectrolyte, are known to form coacervate phases. As protein are complex macromolecules with multiple different hydrophobic and hydrophilic repeat units, it was hypothesized that the hydrophobic units may broaden the composition window for coacervation as at non-stoichiometric charge ratios hydrophobic groups can associate to stabilize phase separated structures similar to ion-pair interactions. Therefore, a simple synthetic system was investigated to isolate the influence of hydrophobic groups on the phase behavior of an aqueous polyelectrolyte blend. The objective of this work was to investigate if hydrophobically modify poly (methacrylic acid), a synthetic polyelectrolyte, was able to expand the composition window of the coacervate phase. In this work, a series of hydrophobically modified poly (methacrylic acid) and poly (allylamine hydrochloride) were investigated as negatively and positive charged polyelectrolytes, respectively. Poly (methacrylic acid), poly (methacrylic acid)-co-poly (methyl acrylate) and poly (methacrylic acid)-co-poly (ethyl acrylate) and poly (methacrylic acid)-co-poly (isopropyl acrylate) were synthesized by free radical polymerization. The target molar ratio was 9:1, where the hydrophobic acrylate part accounts for 10 mol% of the backbone repeat units. Nuclear magnetic resonance (NMR) was used to characterize the composition of the synthesized polymer. Gel permeation chromatography (GPC) was utilized to determine the molecular weight of the synthesized polymer. The phase separation and coacervate complex formation of poly (methacrylic acid) (PMAA) or its copolymers with poly (allylamine hydrochloride) (PAH) were investigated as a function of salt concentration. Sample turbidity is considered as an indicator of coacervate formation. By comparing the phase behavior plot, the precipitation region broadens with increasing salt concentration. By increasing the hydrophobicity of the poly (methacrylic acid), the coacervate region increased, which indicates coacervation is favored in more complex systems with the hydrophobic regions.
Kevin Cavicchi (Advisor)
Bryan Vogt (Committee Member)
Nicole Zacharia (Committee Member)
71 p.
Polymer Chemistry; Polymers
Polyelectrolytes, coacervate, hydrophobicity

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Citations

  • Wang, Q. (2020). HYDROPHOBICALLY MODIFIED POLYELECTROLYTES TO TUNE THE PROPERTIES OF COACERVATES [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1590750104889183

    APA Style (7th edition)

  • Wang, Qiaoyun. HYDROPHOBICALLY MODIFIED POLYELECTROLYTES TO TUNE THE PROPERTIES OF COACERVATES. 2020. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1590750104889183.

    MLA Style (8th edition)

  • Wang, Qiaoyun. "HYDROPHOBICALLY MODIFIED POLYELECTROLYTES TO TUNE THE PROPERTIES OF COACERVATES." Master's thesis, University of Akron, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1590750104889183

    Chicago Manual of Style (17th edition)

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