| Autor: |
Barrall, G. A., Schmidt-Rohr, K., Lee, Y. K., Landfester, K., Zimmermann, H., Chingas, G. C., Pines, A. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 1/8/1996, Vol. 104 Issue 2, p509, 12p |
| Abstrakt: |
We present here an experimental and theoretical study of the application of two-dimensional exchange nuclear magnetic resonance spectroscopy (NMR) to the investigation of the rotational diffusion of colloidal particles. The theoretical discussion includes the nature of the NMR frequency time-correlation function where the NMR interaction is represented by the chemical shift anisotropy (CSA). Time-correlation functions for the isotropic rotational diffusion of a suspension of colloidal particles containing single and multiple sites are derived in addition to time-correlation functions for the rotational diffusion of a suspension of symmetric top particles containing an isotropic distribution of a single CSA interaction. Simulations of two-dimensional exchange spectra for particles undergoing isotropic rotational diffusion are presented. We performed two-dimensional exchange NMR experiments on a colloidal suspension of spherical poly(methyl methacrylate) (PMMA) particles which were synthesized with a 20% enrichment in 13C at the carbonyl site. Rotational diffusion time-correlation functions determined from the experimental exchange spectra are consistent with the composition of the colloidal suspension. Detailed explanations of the syntheses of the enriched methyl 13C-(carbonyl)-methacrylate monomer and the small quantities of 20% enriched 13C-(carbonyl)-poly(methyl methacrylate) microspheres used for this study are presented. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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