Fluid layers, textures

While such behavior can be seen in achiral LC phases, driven by surface constraints as illustrated in Figure 8.11, further characterization of the phase responsible for the minority domains in the B2 banana phases shows this to be the first unequivocal example of a bulk fluid conglomerate. It is worth noting here that the EO behavior of the majority domains is achiral Stripes parallel to the layers switch to a SmA-like focal conic texture, which is identical for both signs of the field, as can be seen in Figure 8.22. This EO behavior very clearly appears achiral when observing the switching in motion. 

LamIso, LamN, and LamSm phases, where the layers of the rod-like molecular cores are separated by the layers formed by the disordered semiperfluorinated lateral chains. In the LamSm and LamN phases there is orientational correlation of the aromatic cores in adjacent layers, leading to birefringence and typical optical textures. The absence of a long range positional correlation of the in-plane periodicity of the layers in the LamSm phase (LamSm/dis phase) indicates only a weak coupling of these layers by the layers of the fluid chains. 

As remarked in chapter 1, the nematic state is named for the threads that can be seen within the fluid under a microscope (fig. 1.1.6(a)). In thin films sandwiched between glass plates these threads can be seen end on. A typical example of the texture in a plane film of thickness about 10 /tm between crossed polarizers - the structures a noyaux or schlieren textures - is given in fig. 1.1.6(6). The black brushes originating from the points are due to line singularities perpendicular to the layer. In analogy with dislocations in crystals, Frank proposed the term disinclinations , which has since been modified to disclinations in current usage. 

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