Variation in the fluorine/carbon elemental ratio in PVDF due to 90 keV D+ implantation

The elemental ratio of fluorine and carbon (F/C) in Polyvinylidene fluoride (PVDF) has been measured using 360 keV D+ Rutherford backscattering (RBS) with the varying 90 keV D+ ion dose. From a virgin value of 1, this ratio reduces sharply with ion dose and saturates at a value of 0.37 corresponding to a very high fluence of 3.58 x 1016 D+ cm-2 (14.30 x 108 Gy). Radiolytically evolved gas analysis (REGA) employing residual gas analyser (RGA) shows radiolytical evolution of HF and H2, without any indication of carbonous species. A negligible depletion in carbon edge and nearly 60% depletion in the F edge clearly depicts the formation of double bonds in the C-C-C back-bone of the macromolecule without its scission. The depletion profile of F as observed on the edge of C in the RBS spectrum is nearly flat with a tendency to increase in depth. The radiation saturated PVDF having a different F/C ratio is thought to have some exotic physical and chemical properties. (author)