Using chiral tactoids as optical probes to study the aggregation behavior of chromonics

Significance Confined liquid crystals occupy a sweet spot in their continued relevance to a host of fundamental studies as well as being exploited for many technological applications. We report on interesting phenomenology in a particularly exciting class of liquid crystals called chromonics by observing the director configurations in tactoids as the phase boundary is traversed. Unique chiral structures in chromonic tactoids are rationalized by appealing to the variation of the aggregate lengths as the concentration and temperature change. We arrive at an interesting conclusion that higher concentrations have shorter aggregates at the nematic–biphasic transition temperature. Our study opens up pathways to exploit this unique class of water-soluble liquid crystals for a host of potential applications while tuning their concentration and temperature.