The domain sizes of a range of diblock polymers have been measured using solid-state NMR spin diffusion experiments carried out under fast magic angle spinning (MAS). 1H-1H exchange spectra were acquired at a range of mixing times and the results displayed effects due to both intra-domain and inter-domain spin diffusion. By fitting the data to an initial rate approximation domain sizes and spin diffusion coefficients were calculated. Simulations were also carried out to determine the impact of T1 relaxation during the experimental mixing time. The spin diffusion coefficient of polystyrene has also been studied under a variety of different conditions. Increasing MAS rate caused a decrease in the spin diffusion coefficient and at the fastest spinning speeds the rate of spin diffusion was much reduced. Temperature changes were shown to have little effect on the spin diffusion coefficient. The incorporation of recoupling sequences into the experimental mixing time was also studied. Solid-state NMR was also used to study a selection of hydroxyapatite nanoparticle/organic dispersant molecule composite materials with potential biomedical applications. 1H-31P correlation experiments were used to investigate the interaction between the dispersant molecules and the surface of hydroxyapatite nanoparticles. The spectra suggested that the dispersant molecules containing polylactic acid interacted with the surface of the nanoparticle via the polymer chain. Whereas dispersant molecules with an aliphatic chain appeared to interact with the particle via their head group. The results from DNP spectra, which selectively enhanced the surface regions, also supported this conclusion.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:719533 |
| Date | January 2017 |
| Creators | Knight, Lyndsey |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/41179/ |
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