No abstract

Fan-shaped textures of hexagonal mesophases of lyotropic systems are often striated. These striations are due to a thermomechanical undulation of the columns. We measure their wavelength and amplitude in the lyotropic mixture C12E06+water. /@ dtait de l'ordre de 40 I (B est le module de compressibilit6 du r6seau hexagonal et If le module de courbure des colonnes). Cette valeur est en accord qualitatif avec celles trouv6es par rayons X (11) ou par la m6thode du joint de grain (10). Par ailleurs, nous avons trouv6 que le module de cisaillement ~1 du r6seau hexagonal est environ 5 1 lo fois plus petit que B, en accord avec les exp6riences de rayons X (16).

No abstract

A simplified model of an inclusion represented by (+1)-wedge disclination and two accompanying (−1/2)-wedge disclinations on the surface of inclusion in smectic C free standing films is used to describe the elastic interaction of inclusions. The orientation of the axis connecting positions of all three disclinations relatively to the director orientation at far distances due to elastic anisotropy is investigated. The configuration with the lowest director perturbations and the lowest anisotropy elastic energy is such that the axis connecting disclinations is parallel to the distant director orientation. The interaction between inclusions at far distances is quadrupolar. The chaining of inclusions is approximately described considering their repulsion due to molecular anchoring at inclusion surfaces.PACS : 61.30.Jf