POSITIONAL ANCHORING OF SMECTIC LIQUID-CRYSTALS

Positional anchoring of the smectic-A (S(A)) liquid crystal 40.8 at a glass plate interface is measured with a micromechanical technique: stress oscillations at layer thickness scale are observed under shear normal to the layers. Similar oscillations are observed on its smectic-B phase, and previously in plastic crystals. These oscillations are explained by shear-induced surface melting and recrystallization. The corresponding S(A) positional anchoring energy is approximately 10(-8)-10(-9) J/m2. This unidimensional periodic melting is a model for solid friction in soft matter.