Faceting of Soft Crystals

The denomination “soft crystals” has been coined by Nozières et al. with the purpose to mark out a special class of liquid crystalline phases—thermotropic and lyotropic cubic mesophases. Their structure, being periodic in three dimensions, is crystalline. At the same time, it is also liquid because contents of huge unit cells are partially liquid. Due to such “liquid crystalline” structures, cubic mesophases have special physical properties such as the “soft elasticity.” Here, we are dealing with another salient property of soft crystals—faceting of their interfaces. We focus on several topics such as (1) special methods allowing observation of faceted shapes, (2) description and classification of characteristic shapes seen as fingerprints of space group symmetries, (3) new phenomena occurring in faceted mesophases.