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You searched for subject:(Electrostatic repulsion). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Tsao, Joanna. Role of surface roughness for colloidal interactions in aqueous media.

Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech

The stability of colloidal dispersions is important for many industrial applications, but there are often discrepancies between theoretical descriptions and experimental observations of surface roughness effects, in part because experimental methods used to vary surface topography simultaneously vary surface chemistry. This work sought to experimentally isolate surface roughness effects on colloidal interactions and to specifically examine how surface roughness modulates the electrostatic, van der Waals, and depletion interactions. Roughness effects on these interactions were determined by measuring particle-plate interactions using total internal reflection microscopy with colloidal probe particles of varied surface topography but similar surface chemistry. Results indicate a systematic weakening of the van der Waals attraction as well as an enhancement of the electrostatic repulsion with increasing particle surface roughness. Increasing surface roughness was also shown to suppress the depletion interaction, a phenomenon that has been predicted theoretically but has never been shown for particles that differed only in surface topography. This experimental work demonstrates the influence of surface topography on the DLVO and depletion interactions and can hopefully be used as a benchmark for future, improved models for surface roughness effects on colloidal interactions. Advisors/Committee Members: Behrens, Sven H. (advisor), Breedveld, Victor (committee member), Champion, Julie (committee member), Meredith, Carson (committee member), Yiacoumi, Sotira (committee member).

Subjects/Keywords: Surface roughness; Total internal reflection microscopy; Electrostatic repulsion; Van der Waals attraction; Depletion interactions

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tsao, J. (2016). Role of surface roughness for colloidal interactions in aqueous media. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59136

Chicago Manual of Style (16th Edition):

Tsao, Joanna. “Role of surface roughness for colloidal interactions in aqueous media.” 2016. Doctoral Dissertation, Georgia Tech. Accessed September 23, 2019. http://hdl.handle.net/1853/59136.

MLA Handbook (7th Edition):

Tsao, Joanna. “Role of surface roughness for colloidal interactions in aqueous media.” 2016. Web. 23 Sep 2019.

Vancouver:

Tsao J. Role of surface roughness for colloidal interactions in aqueous media. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2019 Sep 23]. Available from: http://hdl.handle.net/1853/59136.

Council of Science Editors:

Tsao J. Role of surface roughness for colloidal interactions in aqueous media. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/59136

2. Easter, Nickolas J. Interfacial behavior of RNA-free MS2 bacteriophage particles.

Degree: MS, 0231, 2011, University of Illinois – Urbana-Champaign

The effect of genomic material on the effective surface charge a viral capsid was investigated in this study. The RNA of bacteriophage MS2 was removed and the empty capsid characterized and compared to intact MS2. Transmission electron microscopy was used to ensure that the MS2 capsid was intact and RNA removed. Electrophoretic mobility, aggregation kinetics and kinetics of deposition on silica surface were studied for these two nanoparticles. The isoelectric point of MS2 and RNA-free MS2 were found to be 3.4 and 3.2 respectively, found by varying pH at a constant ionic strength. The electrophoretic softness, found by varying ionic strength and constant pH, found that MS2 was 2.1 nm and that RNA-free MS2 was 1.6 nm, a slightly harder particle. Electrophoretic mobility results of these two particles are similar in solution containing Na+ or Ca2+ or Mg2+ up to ionic strength of 600 mM. Similar aggregation kinetics of MS2 and RNA-free MS2 measured by time-resolved dynamic light scattering at increasing ionic strengths of Na+, Ca2+ and Mg2+ cations were observed. No significant aggregation was observed for both types of particles in solutions containing up to 600 mM NaCl. Insignificant aggregation at high ionic strength suggests an important role of steric repulsion. Using a Quartz Crystal Microbalance, RNA-free MS2 attachment efficiency was found to be higher than MS2. This can be explained by more steric repulsion by the untreated MS2 particles. Similarity in electrophoretic mobility and aggregation of these two particles suggest that for non-magnetic nanoparticles, surface properties are dominant. Advisors/Committee Members: Nguyen, Thanh H. (advisor).

Subjects/Keywords: Aggregation kinetics; Aquatic system; Bacteriophage MS2; Deposition Kinetics; Divalent Salt; Electrostatic interactions; Empty Capsid; Monovalent Salt; Negative charge; Steric repulsion; Time-resolved dynamics

…from the decreased electrostatic interactions at the IEP. Langlet et al. (2008)… …aggregation resulted from decreases in electrostatic repulsive intereactions as the IEP of the virus… …repulsive electrostatic and retarded van der Waals interactions. The following expression was used… …to calculate the electrostatic double-layer interaction energy (Hogg et al. 1966)… …is no significant aggregation at higher Na+ concentrations, steric repulsion may be the… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Easter, N. J. (2011). Interfacial behavior of RNA-free MS2 bacteriophage particles. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/24056

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Easter, Nickolas J. “Interfacial behavior of RNA-free MS2 bacteriophage particles.” 2011. Thesis, University of Illinois – Urbana-Champaign. Accessed September 23, 2019. http://hdl.handle.net/2142/24056.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Easter, Nickolas J. “Interfacial behavior of RNA-free MS2 bacteriophage particles.” 2011. Web. 23 Sep 2019.

Vancouver:

Easter NJ. Interfacial behavior of RNA-free MS2 bacteriophage particles. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2011. [cited 2019 Sep 23]. Available from: http://hdl.handle.net/2142/24056.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Easter NJ. Interfacial behavior of RNA-free MS2 bacteriophage particles. [Thesis]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/24056

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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