Thesis
In situ measurements of interfacial concentration enhancement in solutions
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17532
- Person Identifier (Local)
- 202056359
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Crystallisation is a widely used separation process for the purification of chemical and pharmaceutical compounds during manufacturing. Crystal nucleation is the first step in the crystallisation process and typically proceeds by means of a heterogeneous mechanism, where compounds originally dissolved in solution form a new crystal on surfaces such as vessel walls, impellers or particles suspended in solution. However, comprehensive understanding of crystal nucleation is still lacking despite decades of investigation dedicated into elucidating various nucleation mechanism elucidation. Heterogeneous nucleation is also influenced by the presence of a surface. Molecular level solution behaviour at surfaces is not well understood and it is usually assumed that the solution composition at the surface is the same as in the bulk solution. This thesis utilises surface measurement techniques, primarily surface plasmon resonance (SPR) spectroscopy, to conduct novel in situ measurements of aqueous solutions at solid interfaces and investigate the interfacial concentration enhancement when these solutions are in contact with a solid interface, which has been predicted in recent simulation studies. A comprehensive workflow was developed for in situ SPR measurements, modelling of SPR spectra and fitting of experimental data to provide quantitative assessment of interfacial concentration enhancement in solutions. The developed workflow was applied to undersaturated aqueous glycine and urea solutions on bare gold chips and on gold chips coated with an ultrathin polystyrene layer. The results showed a strong evidence of interfacial concentration enhancement at both gold and polystyrene surfaces for glycine and urea solutions at all concentrations investigated. The investigated solutions were undersaturated to allow for development and validation of experimental protocols in the absence of crystal formation. However, the experimental protocols and workflows introduced here can be used to study supersaturated solutions, where the interfacial concentration enhancement effect confirmed in this work is expected to play a significant role in heterogeneous nucleation. Through systematic investigation of the effects of interfaces and solution concentrations on interfacial concentration enhancement in solutions, this work provides new insights into solution behaviour at interfaces and will help to develop better understanding of heterogeneous crystal nucleation phenomena.
- Advisor / supervisor
- Lau, Aaron
- Sefcik, Jan
- Resource Type
- DOI
Relations
Items
| Thumbnail | Title | Date Uploaded | Visibility | Actions |
|---|---|---|---|---|
|
|
PDF of thesis T17532 | 2025-11-11 | Public | Download |