NMR-STUDIES OF WATER IN POLYIMIDE FILMS

Commercial polyimide films containing up to similar to 3 wt % water ha ve been studied by proton, deuteron, and oxygen-17 nuclear magnetic re sonance (NMR). Comparisons between NMR results and previous dielectric relaxation (DR) results for a variety of Kapton films show that there is a one-to-one correspondence between specific dielectric loss peaks and features of the H-2 or O-17 NMR spectre. It is concluded that wat er molecules, which interact only weakly with the polymer, reside in t he polyimide matrix in two configurations, randomly oriented single mo lecules and chains of water molecules oriented perpendicular to the pl ane of the film. The correspondence between NMR and DR observed in wat er in Kapton extends to water in Upilex and to methanol and acetic aci d in Kapton. (C) 1995 John Wiley & Sons, Inc.