# Chiral Chromonics Confined in Spherical Geometries
## 7 Conclusions  
This review was devoted to the last experimental results obtained in the field of chiral chromonic liquid crystals confined in spherical geometries. In the scientific community, there is a growing interest in studying the fundamental properties of these water-based materials in this highly symmetrical confinement that allows researchers to amplify their peculiar elastic properties.  
After a quick introduction on the self-assembly properties of chromonics, we focused on the optical textures that are observed on thermotropic chiral liquid crystals when confined in spherical geometry. This step was necessary as the textures are explained in terms of the director configuration inside the microspheres and it helps in understanding the supramolecular aggregates configuration in nematic and chiral chromonics. In this perspective, the experimental results obtained on native chiral chromonics in the same type of confinement were reported. Finally, a complete description of the behavior of the two model chromonics confined in the microspheres, DSCG and SSY, using different confining matrices and doping them with different chiral dopants, was reported.  
The experiments carried out on DSCG showed that the typical textures observed in thermotropic liquid crystals, for example the Frank-Pryce, could be obtained in chiral chromonics. This was an important achievement since a similar structure previously was reported only for native chiral chromonics as cellulose nanocrystals.  
To highlight the role of chiral dopants in the torsion of the supramolecular aggregates, X-ray diffraction experiments were carried out and it was found that the chiral molecules tend to bind to the outside of the DSCG cylindrical aggregates, favoring their twist. This result was confirmed for two amino acids: L-alanine and trans-Hyp.  
On the other hand, SSY was demonstrated to be a material that the supramolecular aggregates were difficult to torque, and the effect of the chiral dopants were dependent on the type of amino acid used.  
One of the main differences between DSCG and SSY was their molecular flexibility, which could be the key parameter for the design of new materials in which the chirality could be easily amplified. Overall, these results can be useful in fundamental studies of the defects in the frustrated liquid crystalline phases and may foster the development of new chromonic liquid crystals.  
Finally, chromonics are not yet used for practical applications due to issues in their stability, even if, in recent years, their use as sensors has been foreseen. At present, no application of these materials in their chiral nematic phase has been envisaged. However, the present results could lead to their application in the temperature sensor field.  
Conceptualization, M.P.D.S. and F.C.; methodology, M.P.D.S. and F.C.; writing--original draft preparation, M.P.D.S. and F.C.; writing--review and editing, M.P.D.S., L.S. and F.C.; supervision, M.P.D.S. and F.C. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the following projects: PON ARS01_00401-DEMETRA, CUP: B24I20000080001. L.S. wishes to acknowledge the support from MIUR, PON ARS01_00568-\"S.F.I.P.A.CRO.DE.\", CUP: B29C20000360005.  
Data Availability Statement: Data sharing not applicable.  
The authors declare no conflict of interest.