Elliptical diffusion of dye in hexagonal columnar polycatenar mesophases

We have studied polycatenar compounds which exhibit hexagonal columnar meso phases. In the planar orientation of these mesophases, the elliptical diffu sion of the dissolved dyes is visualized by taking several pictures of the sample. The diffusion ratio D-parallel to/D-perpendicular to is deduced for these columnar mesophases. Furthermore, using a classical optical absorpti on technique, we present measurements of dye diffusion in the same mesophas es. The diffusion constants are measured in two geometries, along and perpe ndicular to the columns. The diffusion anisotropy ratios are in agreement w ith those deduced from the ellipse axes. The structure of these new columna r mesophases exhibited by rod-like mesogens is compared with that of disk-l ike mesogens.