ISSN:
0887-6266
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Rutherford backscattering spectrometry with a 2.1-meV He2+ion beam is used to measure the diffusion of iodine into polyamic acid and polyimide films. The iodine diffusion coefficient D decreases from its initial value of about 2X10-13cm2/s in polyamic acid to approximately 1.4 × 10-15cm2/s in partially cured polyimide, but then increases to a value of nearly 1.5 × 10-14 cm2/s in fully cured polyimide. This dramatic increase in D cannot be attributed to the “in-plane” biaxial orientation of the polyimide molecules since indential D's were found with isotropic specimens. Microvoids less than 2 nm in size caused by water and carbon dioxide formation during imidization may, however, give rise to the observed behavior. The results demonstrate that Rutherford backscattering spectrometry with its excellent depth resolution (better than 30 nm) and good sensitivity (50 ppm iodine can be detected) is very useful for measuring the diffusion of slowly diffusing species in glassy polymers.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1986.090240205
