Thin Nematic Films: Metastability And Spinodal Dewetting

We present new results about the stability of 5CB nematic films spun cast onto silicon wafers. We observe experimentally the dewetting of thin films while thick ones remain stable. We interpret this behavior as a competition between elasticity and van der Waals forces. At later stages, the experimentally observed dewetting instability leads to the formation of structures (islands) which grow and finally merge to form a film of uniform thickness. We show that the islands' characteristic size $L(t)$ scales as t1/3 as expected from late stage growth theories.