Spherical Confinement of Chromonics: Effects of a Chiral Aminoacid

Abstract

Induced or spontaneous chirality in natural systems is an intriguing issue. In recent years, a lot of attention has been focused on chirality of chromonic liquid crystals, a class of materials that is able to self-assemble in columnar structures. However, the mechanism involved in the arising of chirality in these materials, that starts at the molecular level and controls the supramolecular structure, is poorly understood; however, it is certainly affected by ionic strength. In this work we present the results obtained doping Cromolyn, a chromonic material, with a strong helical-twisting-power peptide, and confining it in a spherical geometry. We demonstrate, by means of optical polarized microscopy and structural analysis, that both the geometrical constraint and the presence of the chiral dopant enhance the chiral effect; we also demonstrate that they favor the rise of a highly ordered helical superstructure, that may be optimized upon adding an ionic dye to the system. Finally, we report a procedure for the preparation of free-standing polymeric films, embedding and preserving the microspheres, and paving the way for the creation of biocompatible and eco-friendly optical devices to be used in the sensor and anticounterfeiting fields.

Sunset Yellow Confined in Curved Geometry: A Microfluidic Approach

“…The production of well-defined size-dependent optical textures is the first crucial step toward the use of chromonic microspheres for practical applications. In particular, it has been recently demonstrated that the optical topology of microspheres degrades irreversibly over time due to temperature . Degradation can be slowed down by keeping the samples at 5 °C and can be avoided if samples are stored at −18 °C.…”

“…In particular, it has been recently demonstrated that the optical topology of microspheres degrades irreversibly over time due to temperature. 48 Degradation can be slowed down by keeping the samples at 5 °C and can be avoided if samples are stored at −18 °C. This paves the way for the fabrication of new biocompatible time–temperature indicators that can be used to monitor the cold food chain.…”