Dewetting of solvated polymer brushes by thin liquid films

Thin liquid oligostyrene films on top of a surface-anchored, polystyrene brush-solvated by the oligostyrene itself - roughen spontaneously. Using optical phase-interference microscopy and nuclear reaction analysis we have characterized the topography of such roughened films. We see that the undulations formed reach down at most to approximately the top of the solvated brush, but not to the underlying solid substrate on which the brush is anchored. Possible origins for this behaviour are discussed in terms of a picture wherein the solvated brush is regarded as a quasi-solid substrate for the liquid film on top.