Defects core structure 373-4 disclinations

Topologically, it turns out that the helical structure of the cholesteric cannot be deformed continuously to produce a cubic lattice without creating defects. Thus BP I and BP II are unique examples in nature of a regular three-dimensional lattice composed of disclination lines. Possible unit cells of such a disclination network, arrived at by minimizing the Oseen-Frank free energy, are shown in fig. 4.8.3. The tubes in the diagram represent disclination lines, whose cores are supposed to consist of isotropic (liquid) material. Precisely which of these configurations represents the true situation is a matter for further study. 

FIGURE 12.52 The combination of basic structural units into microdomains within a carbon fiber (a) skin region (b) core region (c) a hairpin defect and (d) a wedge disclination. (From Bennet, S.C. and Johnson, D.J. in Society of Chemical Industry, London, p. 377, 1978.)... 

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