Thin nematic films: Metastability and spinodal dewetting

We present new results about the stability of 5CB nematic films spun cast o nto silicon wafers. We observe experimentally the dewetting of thin films w hile thick ones remain stable. We interpret this behavior as a competition between elasticity and van der Waals forces. At later stages, the experimen tally 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 t(1/3) as expe cted from late stage growth theories. [S0031-9007(99)08781-5].