%0 Journal Article %J Journal of Chemical Physics %D 1996 %T Rotational diffusion measurements of suspended colloidal particles using two-dimensional exchange nuclear magnetic resonance %A Barrall, G. A. %A Schmidt-Rohr, K. %A Lee, Y. K. %A Landfester, K. %A Zimmermann, H. %A Chingas, G. C. %A Pines, A. %K scattering %X

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 C-13 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 C-13-(carbonyl)-methacrylate monomer and the small quantities of 20% enriched C-13-(carbonyl)-poly(methyl methacrylate) microspheres used for this study are presented. (C) 1996 American Institute of Physics.

%B Journal of Chemical Physics %V 104 %P 509-520 %8 Jan 8 %@ 0021-9606 %G English %U ://WOS:A1996TN83700009 %N 2 %M WOS:A1996TN83700009 %! Rotational diffusion measurements of suspended colloidal particles using two-dimensional exchange nuclear magnetic resonance %R Doi 10.1063/1.470847