Polymers multiple scattering sequences

In the case of Cu deposition, the initial persistence of the PET pealcs is believed to be related to Cu penetration into the polymer. A confirmation of the Cu atom incorporation underneath the PET surface has been obtained by Ion Scattering measurements. For Al deposited on PET, the ISS spectra show a well-defined single scattering peak due to collisions with Al surface atoms, whereas in the case of Cu deposition, only a broad distribution with a high energy edge at Che Cu kinematic factor is observed. This indicates that essentially no Cu atoms are present in the uppermost monolayer since mainly inelastic and multiple collisions sequences are detected. Diffusion of Cu into the polymer bulk has also been mentioned in the literature for polyimide B substrates. 

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