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

For the purpose of identifying surface conformations, the valence XPS spectra of mats of polyethylene single crystals as prepared from the solution and after annealing are reported and compared with the spectrum of a pressed pellet of hexatriacontane. The relative intensity of the two ''C-C peaks'' in the inner-valence region exhibit significant variations 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 the annealed and pellet samples, on the other hand.