Basic principles of static proton low-resolution spin diffusion NMR in nanophase-separated materials with mobility contrast.

摘要: We review basic principles of low-resolution proton NMR spin diffusion experiments, relying on mobility differences in nm-sized phases inhomogeneous organic materials such as block-co- or semicrystalline polymers. They are use for estimates domain sizes and insights into nanometric dynamic inhomogeneities. Experimental procedures limitations mobility-based signal decomposition/filtering prior to addressed the example yet unpublished data poly(ϵ-caprolactone), PCL. Specifically, we discuss technical aspects quantitative, dead-time free detection rigid-domain signals by aid magic-sandwich echo (MSE), magic-and-polarization-echo (MAPE) double-quantum (DQ) magnetization filters select rigid mobile components, respectively. Such general reliable fitting approaches phase composition determinations. Spin studies at low field using benchtop instruments challenged rather short (1)H T1 relaxation times, which calls simulation-based analyses. Applying these, combination with determined small-angle X-ray scattering, have coefficients D PCL (0.34, 0.19 0.032nm(2)/ms crystalline, interphase amorphous parts, respectively). further address thermal-history effects related secondary crystallization. Finally, state knowledge concerning connection between values locally atomic level, (13)C CP- REDOR-based "(1)H hole burning" procedures, those obtained calibration is summarized. non-trivial dependence magic-angle spinning (MAS) frequency, a minimum under static local maximum moderate-MAS conditions, highlighted.