EVIDENCE IN THE XPS VALENCE-BAND OF THE FOLD STRUCTURE AT THE SURFACEOF POLYETHYLENE LAMELLAE

For the purpose of identifying surface conformations, the valence XPS spectra of mats of polyethylene single crystals as prepared from the s olution and after annealing are reported and compared with the spectru m of a pressed pellet of hexatriacontane. The relative intensity of th e two ''C-C peaks'' in the inner-valence region exhibit significant va riations that are related to the chain folds occurring at the surface of the lamellae, on the one hand, and to planar zig-zag segments for t he annealed and pellet samples, on the other hand.