Chemical interaction of Fe, Ni and Au with poly(vinyl chloride) and poly(tetrafluoroethylene) during thermal evaporation and the effect of post-metallization X-ray irradiation studied by in situ X-ray photoelectron spectroscopy - Polyimides and Other High Temperature Polymers - page 355

The results from this investigation show that X-ray modification of the
Ni/PFTE and Fe/PTFE interfaces can increase the extent of compound formation
in the metal/polymer interfacial region. Based on the empirical observation [12,
31-33] that compound formation in the metal/polymer interfacial region is corre-
lated with improved adhesion characteristics, the effect of post-metallization X-
ray irradiation in these systems may have technological significance. It should be
pointed out, however, that any strategy for increasing the interlayer thickness de-
rived from X-ray induced modification is only viable if the metallic overlayer is
less than the X-ray penetration depth.
5. CONCLUSIONS
The reactivity of Fe, Ni and Au was investigated on PVC and PTFE as well as the
effect of post-metallization X-ray irradiation. On PVC, Fe, Ni and Au were all
found to be reactive, although the extent of reaction varied, while on PTFE only
Fe and Ni were reactive. These results, as well as those from other metal/polymer
systems are rationalized in terms of the difference between M-X (X = F, Cl) and
C-X bond strengths. Post-metallization modification by X-rays was found to re-
sult in the formation of metal chloride at the Fe/PVC interface and metal fluoride
at the Fe/PTFE and Ni/PTFE interfaces. The enhanced metal halide production
during post-metallization X-ray irradiation is postulated to arise from the creation
of active chlorine/fluorine species in the polymer and their subsequent reaction
with the metallic overlayer rather than an effect associated with metal migration
into the bulk.
Acknowledgements
Support for this research was provided by a National Science Foundation
CAREER award (# 9985372). This work was carried out in the surface analysis
laboratory at Johns Hopkins as part of the Materials Research Science and Engi-
neering Center, funded through the National Science Foundation.
REFERENCES
1. R.L. Opila, K. Konstadinidis and S.O. Conner, in Polymer Surfaces and Interfaces: Characteri-
zation, Modification and Application , K.L. Mittal and K.-W. Lee (Eds.), p. 179, VSP, Utrecht
(1997).
2. V. Zaporojtchenko, T. Strunskus, K. Behnke, C.V. Bechtolsheim, M. Kiene and F. Faupel, J.
Adhesion Sci. Technol. , 14, 467 (2000).
3. E. Sacher, J.J. Pireaux and S.P. Kowalczyk (Eds.), Metallization of Polymers, ACS Symp. Ser.
440 , Amer. Chem. Soc., Washington, DC (1990).
4. K.L. Mittal (Ed.), Metallized Plastics 2: Fundamental and Applied Aspects , Plenum Press, New
York (1991).
5. K.L. Mittal and J.R. Susko (Eds.), Metallized Plastics 1: Fundamental and Applied Aspects ,
Plenum Press, New York (1989).