The DIVAM Filter: A NMR Signal Selection Method that is Tunable to Various Structural Domains Within Semicrystalline Materials

摘要

The selection mechanism in the Discrimination Induced by Variable Angle Minipulse (DIVAM) sequence as a domain filter is investigated using spin dynamics simulations. Experiments on poly(vinylidinefluoride) (PVDF) show that 19{sup left}F DIV AM selects on the basis of relaxation and the chemical shielding anisotropy interaction, where the role of the latter was confirmed by the simulations. The DIVAM filter was applied in domain selective 13{sup left}C{1{sup left}H, 19{sup left}F} experiments on poly[bis(trifluoroethoxy)-phosphazene] (PBFP). The resulting spectra were sensitive to morphological changes in the crystalline domain, which was not previously observed with 19{sup left}F and 31{sup left}P methods.