Planar anchoring and surface melting in the smectic-A phase

Emmanuelle Lacaze (1) , Jean-Philippe Michel (1) , Michel Alba (2) , Michel Goldmann (1)

1 INSP - Institut des Nanosciences de Paris
2 LLB - UMR 12 - Laboratoire Léon Brillouin

We study ultrathin films of 8CB in planar anchoring on a MoS(2) inorganic substrate. We evidence an anchoring breakage for 60-nm-thick films, in favor of the homeotropic anchoring at the air interface. This allows one to determine the 8CB-MoS(2) smectic anchoring energy. We then demonstrate for films thinner than 60 nm that, under the homeotropic bulk, an intermediate film remains in planar anchoring, associated with a melting of the smectic layers close to the substrate. Such a melting could be general for planar or tilted anchorings and we show that, for strong anchorings, the anchoring energy can be driven by the deformations of this intermediate nematic film.

Domaines: Matière Condensée [cond-mat]

Emmanuelle Lacaze, Jean-Philippe Michel, Michel Alba, Michel Goldmann. Planar anchoring and surface melting in the smectic-A phase. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2007, 76 (4, 1), pp.041702. ⟨10.1103/PhysRevE.76.041702⟩. ⟨hal-01292979⟩