Doctoral Dissertations

Minghang Chen

Keywords and Phrases

Particle characterization; Salt effect; Electroviscous effect; Surface water; Random close and hexagonal packing

Abstract

"Colloidal Unimolecular Polymer (CUP) particles are a new genre of material formed by self-assembly into spheroidal particles due to the effect of hydrophilic/hydrophobic interactions of the polymer with a change in the solvent. The particle sizes were characterized by means of Dynamic Light Scattering with corrected viscosities instead of water's viscosity. The distribution of particle size agreed well with the distribution of molecular weight proving that the polymer had undergone unimolecular collapse. The rheology study shows the presence of surface water and its significant effect on the rheology. The primary and secondary electroviscous effects were also found to play roles when the suspension was in dilute to semi-dilute regime. When the volume fraction of particles were higher than 0.15, the rheology behavior fit well with Krieger-Dougherty equation. The thickness and the density of surface water were calculated to be 0.57nm and 1.0688 g/cm³ respectively. When small amounts of external electrolytes were added, (<2% by weight), the viscosity of the suspensions (<0.06 by volume) dropped due to screening effect of the added electrolytes. When the volume fraction of the suspension increased or the addition of electrolytes increased, the viscosities of suspension increased sharply at different critical points. The CUPs showed remarkable surface activities, which increase with molecular weights. The calculated average equivalent area occupied by each particle was much smaller than that of the largest cross-section of the particle indicating that the liquid-solid interface contact angle of the particle was quite low, close to 10º"--Abstract, page iv.

Advisor(s)

Van-De-Mark, Michael R.

Committee Member(s)

Woelk, Klaus
Ma, Yinfa
Schuman, Thomas P.
Morrison, Glenn

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Sponsor(s)

Missouri University of Science and Technology. Department of Chemistry.
Missouri University of Science and Technology. The Missouri S&T Coatings Institute

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2013

Journal article titles appearing in thesis/dissertation

  • Rheological studies on colloidal unimolecular polymer (cup) particles suspensions.
  • Gel point behavior of colloidal unimolecular polymer (cup) particles.
  • Surface tension of colloidal unimolecular polymer particles at the N₂/water interface.
  • Rheology studies on 3-7nm colloidal unimolecular polymer (CUP) particles in presence of NaCl.
  • Molecular weight (Mn) and functionality effects on CUP formation and stability.

Pagination

xix, 147 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2013 Minghang Chen, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Polymer colloids -- TestingPolymer colloids -- Mathematical modelsPolyacrylamide gel electrophoresisPolymers -- RheologyQuasielastic light scatteringParticle size determinationSurface tension -- MeasurementPolyelectrolytes -- TestingMacromolecules -- AnalysisBiomolecules -- AnalysisStructure-activity relationships (Biochemistry)

Thesis Number

T 10362

Electronic OCLC #

858610228

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Included in

Chemistry Commons

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