The dynamical characteristics of water absorbed in Nafion are investigated using n.m.r. At temperatures below the dynamical transition temperature, T t, relaxation rates indicate mobility associated with a fluid but the derived motional activation energies are similar to those of ice. This indicates a well ordered supercooled fluid consisting of hydrogen bonded water structures. The correlation time t c is found to have a Gaussian dependence on the surface area to volume ratio, unlike simple porous systems. We have shown that the surface area depends on r 2.5. We feel that this is due to the irregular nature of the surfaces of the clusters.
Посилання на статтю:
N.m.r. relaxation in Nafion—the low temperature regime / Bryce MacMillan, Allan R. Sharp, Robin L. Armstrong // Polymer. – 1999. – N 40. – P. 2481–2485.