The state of water and sodium ions in poly(N-isopropylacrylamide) gel were studied by differential scanning calorimetry (DSC), and 1H and 23Na NMR. The motional state of water in the gel is restricted at the phase transition point. DSC and 1H NMR suggest that the associated water is considered to be transformed into nonfreezing water on increasing the volume fraction of the polymer. 23Na NMR indicates that the sodium environment is distorted at higher temperatures, leading to an increase for the bound values of both linewidth and chemical shift, which is consistent with the finding that the introduction of Na+ ions into a hydrated gel system increases the amount of nonfreezing water.
|Number of pages||4|
|Journal||Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes|
|Issue number||12 A|
|Publication status||Published - Dec 1 2000|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)