- K. Saalwächter.
Detection of Heterogeneities in Dry and Swollen Polymer Networks by Proton
Low-Field NMR Spectroscopy.
J. Am. Chem. Soc. 125, 14684-14685 (2003).
We report on the implementation of modern proton multiple-quantum NMR methods
for the characterization of molecular order and dynamics in polymer networks and
melts on cost-efficient low-resolution low-field NMR instrumentation. The method
permits the extraction of chain order parameter distributions, and is therefore
sensitive to a heterogeneity of cross-links and other topological constraints.
Data from samples with bimodal network chain length distributions acquired at 20
MHz (0.47 T) are in quantitative agreement with results obtained at high field
(500 MHz). It is shown for the first time that the chain order distribution is
broadened upon swelling, providing evidence for the non-trivial nature of the