Chirality induction in confined chromonics: A case study

Abstract

Chromonic liquid crystals are a sub-category of lyotropic liquid crystalline materials whose self-assembling mechanisms in complex supramolecular structures are still not fully understood. Chirality can be induced in chromonics using chiral aminoacids with alternating results. Understanding the key factors that lead to maximize this phenomenon is important for the design of novel materials able to self-assemble in chiral macroscopic structures with tailored optical properties, as selective reflection.In this work, we present a comparative study involving a not commercial chromonic, a synthesized metal containing chromonic compound [(Bpy-OH)2Ag][CH3COO]H2O, and two model chromonics that behave in different manner with respect to chiral induction. Spherical confinement provides a quick way to qualitatively evaluate the elasticity properties in new materials. Also, optical textures of the metal compound, after doping the material with a chiral moiety, show that its chiral phase is more similar to one of the two model chromonics. This observation points to a role played by the flexibility of the molecular structure that it’s reflected into the resistance of the columnar aggregates to undergo a twist. This last observation can be useful when selecting the most suitable building blocks in designing new materials.