AbstractThe preferential enrichment of specific chemical groups that occur at the surface of three classes of polymers was studied by means of X‐ray photoelectron spectroscopy (XPS or ESCA). The material variables included bulk chemical composition, degree of crystallinity, and crosslinking. It was found that XPS is capable of detecting PET cyclic oligomers that were forced to the surface during crystallization. A new PET surface texture was observed by SEM on PET surfaces from which the oligomer crystals were extracted. A crystalline 1 : 1 alternating copolymer of ethylene/chlorotrifluoroethylene presented a preferential arrangement of ethylene segments closer to the surface relative to the chlorotrifluoroethylene groups. A small amount of contamination strongly affected that surface composition. In linear segmented polyurethanes, enrichment of the surfaces with soft segments occurred. However, this segregation seemed inhibited by crosslinkin
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