ANCHORING STRENGTH ONTO SIMPLE SURFACE EDGE DISLOCATIONS IN AN INDUCED SMECTIC-O FILM

Surface freezing is able to produce thick smectic-O films at the free surface of isotropic droplets of 1-(methyl)-heptyl-terephthalidene-bis -amino cinnamate, which are naturally free from solid contacts. This p articular situation allows us to realize a microbalance for determinin g the anchoring conditions of the director onto the surface edge dislo cations. The director of the film is thus found to be anchored at norm al angle to the simple edge dislocations with an anchoring constant pe r unit length of dislocation independent of the film thickness: k(a) i s similar to 5 x 10(-14) N. This value corresponds to a maximum anchor ing energy approximately 1/25 k(B)T per molecule of the dislocation li ne.