Autophobic behavior of polymers at the melt-elastomer interface

The wetting behavior at the interface of athermal polymer-elastomer couples was investigated experimentally. Using end-linked poly(dimethylsiloxane) ( PDMS) elastomers as model substrates and PDMS liquids of different molecula r weights, we observed a crossover from complete to partial wetting. This b ehavior is analogous to the phenomenon of "wetting autophobicity" at the in terface between polymer melts and polymer brushes and may originate from en tropic effects. The shape of the substrate at the autophobic regime was pro filed by optical phase interference microscopy and found to be undistorted, unlike the theoretical predictions. We suggest that the steady-state confi guration of the melt-elastomer interface may be that of "pseudo partial wet ting".