| Abstract | Angle dependent X-ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS) were used to study the surface composition of two polyether polyurethane block copolymers. Both were synthesised with 2,4-toluene diisocyanate and ethylene diamine as the hard segment, but different soft-segment compositions were used. In one case, the soft segment was polytetramethylene oxide (PTMO) while, in the other case, it was a mixture of PTMO and polyethyleneoxide (PEO). The selection of the two oligomers for the soft segments allowed for an investigation of the influence of an elastomer's polar character on the nature of chemical groups detected at the surface. By following the Cls signal and the atomic concentration of nitrogen with respect to take off angle, it was shown that the surface of the films were depleted in nitrogen containing hard segments. The study also showed that the sample having both PTMO and PEO soft segments displayed a tendency for the PTMO to segregate from the PEO and migrate to the top surface, resulting in a depletion of the top layer in PEO. Static SIMS of this sample confirmed this observation. |
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