Nucleation-induced undulative instability in thin films of nCB liquid crystals

A surface instability is reported in thin nematic films of 5CB and 8CB, occurring near the nematic-isotropic phase transition. Although this instability leads to patterns which are reminiscent of spinodal dewetting (and have been interpreted as such), we show that it is actually based on a nucleation mechanism. Its characteristic wavelength does not depend markedly on film thickness, but strongly on the heating rate.