Quartic coupling and its effect on wetting behaviors in nematic liquid crystals*
Zeng Ming-Yinga),b), Holger Merlitza), Wu Chen-Xua)†
       
Phase diagram for the system, where liquid crystal experiences a first-order phase transition from nematic phase (low temperature and low coupling strength) to paranematic phase at the critical surface (red). In the diagram the blue line is the boundary above which the phase transition disappears, the green one and the light blue one are critical lines across which d S /d z changes its sign. The black line is the phase transition curve without quartic coupling.