Jf. Silvain et al., INFLUENCE OF OXYGEN PARTIAL-PRESSURE ON THE ADHESION OF METALLIC-FILMS EVAPORATED ON PET, Thin solid films, 237(1-2), 1994, pp. 164-171
The influence of a controlled oxygen pressure on the metallization (by
Al, Ag and Cu) of poly(ethylene terephthalate) (PET) has been investi
gated. The structure of the interfaces and of the bulk metallic films
has been characterized using TEM. The laminate peel energy strength ha
s been measured with a standard peel test. The most significant result
s concern the Al/PET laminates: (i) wet and dry adhesion are greatly i
mproved if an oxygen partial pressure higher than 10(-5) mbar is intro
duced during evaporation of the him, and (ii) depending on the oxygen
partial pressure, either metallic Al films with various grain size or
amorphous aluminium oxide films are prepared. No significant improveme
nt in adhesion is observed with an oxygen partial pressure (10(-6) to
10(-4) mbar) during the evaporation of Ag or Cu. These results are dis
cussed in terms of the mechanism of chemical interaction at the metal-
polymer interface. As chemical reactions with oxides or hydroxides are
likely to occur with aluminium, the gas phase interaction would contr
ibute to the oxidation process. Ag and Cu being much less reactive, an
other mechanism involving metal diffusion in the free volume of the po
lymer dominates and the presence of oxygen has almost no effect.