Unique Mechanisms of Colloidal Stability Probed by Surface-Specific Vibrational Spectroscopy
| dc.contributor.advisor | Scatena, Lawrence | |
| dc.contributor.author | Mapile, Ashley | |
| dc.date.accessioned | 2024-12-19T20:07:45Z | |
| dc.date.available | 2024-12-19T20:07:45Z | |
| dc.date.issued | 2024-12-19 | |
| dc.description.abstract | The stability of nanoparticles suspended in a solution, known as colloids, is crucial for their application in drug delivery systems, the solution processibility required for drop-casting films, and the long-term storage or transport of sensitive chemical materials. While current mechanisms for colloidal stability include implicit models of solvation – namely Derjaguin-Landau-Verwey-Overbeek (DLVO) and Flory-Huggins theories – these classical approaches neglect the role of specific solvent-surface interactions. Analyzing these surface-specific interactions in colloidal stability becomes increasingly relevant for nanosized particles, which have a highly accessible surface area compared to their bulk counterparts.This dissertation seeks to understand unconventional mechanisms of colloidal stability that are not explained by traditional theories alone, with oil-in-water emulsions and nanoparticles of metal-organic frameworks (nanoMOFs) as model materials. Leveraging the surface-specific spectroscopic technique, vibrational sum frequency scattering spectroscopy (VSFSS), this work provides a molecular-level understanding of the specific surface interactions that contribute to colloidal stability. In particular, emulsions can be stabilized by a steric layer of polymer alone, with colloidal behavior tunable by pH, electrolyte concentration, molecular weight, and temperature. These sterically-stabilized emulsions find applications in drug delivery systems that must withstand extreme physiological conditions. For bare nanoMOFs, an ordered solvation shell and solvent-metal surface binding contribute to unforeseen long-term stability in common solvents. Additionally, nanoMOFs coated with a polymeric binding agent – similar to those used in the paint industry – yield ultra-strong mixed-matrix membranes for gas separation technologies. Ultimately, this work bridges molecular interfacial chemistry with material properties, emphasizing the importance of understanding mechanisms of colloidal stability. This dissertation includes previously published co-authored material. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/30295 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | All Rights Reserved. | |
| dc.subject | Colloids | en_US |
| dc.subject | Interfaces | en_US |
| dc.subject | Materials | en_US |
| dc.subject | Spectroscopy | en_US |
| dc.title | Unique Mechanisms of Colloidal Stability Probed by Surface-Specific Vibrational Spectroscopy | |
| dc.type | Electronic Thesis or Dissertation | |
| thesis.degree.discipline | Department of Chemistry and Biochemistry | |
| thesis.degree.grantor | University of Oregon | |
| thesis.degree.level | doctoral | |
| thesis.degree.name | Ph.D. |
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