Wetting of Polymer Brushes by a Nematogenic Compound

The spreading of nematic liquid crystal (LC) droplets on polymer brushes has been characterized by optical microscopy and ellipsometry. We observed a first thin precursor film made of pure LC on top of the dry brush which grows with time according to a hypodiffusive law. The penetration of the brush by the LC is then observed. With a thick enough layer, the molecules diffusing into the brush swell it so that a shoulder appears at the edge of the droplet. The evolution of that shoulder is self-similar, confirming that the later process is diffusive.