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 molecular weights, we observed a crossover from complete to partial wetting. This behavior is analogous to the phenomenon of "wetting autophobicity" at the interface between polymer melts and polymer brushes and may originate from entropic effects. The shape of the substrate at the autophobic regime was profiled by optical phase interference microscopy and found to be undistorted, unlike the theoretical predictions. We suggest that the steady-state configuration of the melt-elastomer interface may be that of "pseudo partial wetting".