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Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study
Published on: August 15, 2016
Impediments to the accurate structural characterisation of a highly concentrated emulsion studied using NMR diffusion
Nirbhay N Yadav1, William S Price
1College of Heath and Science, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia.
Journal of Colloid and Interface Science
|July 7, 2009
Summary
Pulsed gradient spin-echo NMR diffusion studies reveal new details in concentrated emulsions. Advanced modeling of coherence features provides insights into droplet size and structure, improving understanding of emulsion properties.
Area of Science:
- Physical Chemistry
- Materials Science
- Nuclear Magnetic Resonance Spectroscopy
Background:
- Pulsed gradient spin-echo (PGSE) NMR with Gaussian phase distribution (GPD) analysis is standard for emulsion structure determination.
- Higher gradient strengths enable PGSE measurements revealing diffusive diffraction effects.
- The GPD approach fails to predict these crucial diffraction-like coherence features.
Purpose of the Study:
- To extend PGSE NMR analysis beyond GPD to include diffusive diffraction effects.
- To utilize coherence features for detailed morphological characterization of emulsions.
- To investigate structural characteristics of highly concentrated emulsions.
Main Methods:
- Employing pulsed gradient spin-echo (PGSE) NMR diffusion measurements.
- Utilizing advanced modeling based on the short gradient pulse approximation (SGP).
- Applying the multiple propagator matrix formalism extension of the SGP approach.
Main Results:
- Observed and analyzed diffusive diffraction coherence features in PGSE NMR spectra.
- Successfully modeled coherence features to extract morphological characteristics like pore size, tortuosity, and connectivity.
- Elucidated emulsion droplet polydispersity by analyzing deviations in coherence features.
Conclusions:
- The advanced SGP-based modeling of PGSE NMR diffusion diffraction coherence features offers superior insights into emulsion structure.
- This method provides crucial information on polydispersity, impacting emulsion stability and functionality.
- The study demonstrates a powerful approach for characterizing complex emulsion systems.
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