Complex crossed lamellar

Complex crossed lamellar structure a layer consisting of aragonite needle crystals with orientations inclined at 45° to the inner portion of the cell. These needle crystals aggregate in a radial manner, forming a conical body, which is arranged nearly perpendicularly to the inner surface of the shell. 

S = solution, (e) Prismatic structure (f) foliated structure (g) crossed lamellar structure (h) complex crossed lamellar structure. 

The initial modulus is determined in the limit of small strain. The initial portion of the force-length curve is usually reversible. The deformation of the disordered interlamellar region is involved and the lamellar structure remains essentially intact. Interpreting the modulus, in terms of the basic structural and molecular parameters that define a semicrystalline polymer, is complex. In this region of very small strain, the primary effect is a rubber-like elastic deformation, whereby chain entanglements and other topological features act as effective cross-links. The total system is constrained by the bounding lamellae and their broad basal planes. 

Oily-streaks are the most usual structural defects in lyotropic lamellar phases. They appear as long bands with a complex inner structure, which subdivide the sample into so-called homeotropic regions where the layers are parallel to the boundaries of the preparation, and thus appears in black between cross nicols. 

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