Morphogenesis of a chiral liquid crystalline droplet with topological reconnection and Lehmann rotation.

Morphogenesis is a hierarchical phenomenon that produces various macroscopic structures in living organisms, with high reproducibility. This study demonstrates that such structural formation can also be observed in a chiral liquid crystalline droplet under a temperature gradient. Through specific control of the temperature change process, we were able to switch the final structure obtained as a result of the formation via the appearance and reconnection of loop defects in the transient state during structure formation. Simultaneously, the existence of the gradient resulted in a characteristic rotational phenomenon called Lehmann rotation, which was prominently induced in the transient state. By demonstrating three-dimensional measurements of the flow field, we revealed the existence of Marangoni convection in the state. Consequently, it is indicated that the convection results in high-speed Lehmann rotation and large structural deformation with topological changes, thereby playing a significant role in the structure formation.