| Abstract: | X-ray photoelectron spectroscopy and scanning electron microscopy are used to follow the effect of uniaxial stretching on the surface composition and morphology of poly(dimethyl siloxane)/poly(chloroprene) blends. Before stretching, the blends exhibit a high surface segregation of siloxane due to an extremely low surface energy of the latter. The stretching gives rise to a substantial drop in the siloxane surface enrichment, whereas the subsequent unloading has the reverse effect. The surface behavior of the blends upon deformation strongly depends on the molecular weight of the siloxane component. Oligomeric siloxane (MW = 2500) shows a much stronger surface depletion with stretching, compared to that observed with a siloxane polymer (MW = 625,000). Furthermore, the surface behavior of the blends of the polymeric siloxane is completely reversible in sample length, whereas the blends of the oligomeric siloxane have different surface compositions on stretching and contraction. © 1996 John Wiley & Sons, Inc. |
