| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5352970 | Applied Surface Science | 2013 | 4 Pages |
Abstract
Depth-dependent positron annihilation Doppler broadening measurements were conducted for polymers with different chemical compositions. Variations of the S parameter with respect to incident positron energy were observed. For pure hydrocarbons PP, HDPE and oxygen-containing polymer PC, S parameter rises with increasing positron implantation depth. While for PI and fluoropolymers like PTFE, ETFE and PVF, S parameter decreases with higher positron energy. For chlorine-containing polymer PVDC, S parameter remains nearly constant at all incident positron energies. It is suggested that these three variation trends are resulted from a competitive effect between the depth-dependent positronium formation and the influence of highly electronegative atoms on positron annihilation characteristics.
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Authors
J. Yang, P. Zhang, G.D. Cheng, D.X. Li, H.B. Wu, Z.X. Li, X.Z. Cao, Q.J. Jia, R.S. Yu, B.Y. Wang,