Liquid-crystalline chiral phase formation and structural transitions of dumbbell-shaped colloids

Abstract Colloidal liquid crystals (LCs) are an emerging class of soft materials that naturally combine the unique properties of both LC molecules and colloidal particles. Chiral LC blue phases are highly attractive in fast optical displays and electrooptical devices, but the formation of chiral structures from achiral colloidal particles is rare. Herein we demonstrate that achiral dumbbell-shaped colloids can assemble into a rich variety of characteristic LC phases, including nematic phases with lock structures, smectic phases, and particularly double-twisted chiral columnar phases. Phase diagrams from experiments and simulations show that the existence and stable regions of different LC phases are strongly dependent on the geometry of colloids. Furthermore, the LC phases can be dynamically tuned by external magnetic fields. This work paves a new route to the development of stimuli-responsive functional LC mesostructures for LC display and laser applications.