Herringbone textures

Even more highly structured variations on the band structure have been reported, such as the helical coarse rope structure in PEG solutions [18] (Figure 11.18) or a torsad structure in HPC solution [100] and a tractor or herringbone texture in thermotropic polyester [101]. 

Figure 7. The origin of the herringbone texture of the M phase This texture develops when the M phase is formed by the concentration of the N phase (by allowing water to evaporate from the edge of the sample). The explanation is the same as that proposed to explain the similar texture of the amphiphile H phase. It is easier to extend a column than to create a new one. This leads to strain in the specimen which is relieved by the creation of multiple fault lines, giving the herringbone appearance.

The herringbone texture of the M phase obtained by allowing a sample in the N phase to become more concentrated by peripheral evaporation. 

Note that the term herringbone is used in two different contexts in chromonic systems at the molecular level, to describe the transverse arrangement of columns in the M phase, and on a much larger scale, to describe the diagonally striped optical texture of the M phase grown by concentration of the N. 

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