Undulated boundaries offer a way to direct the assembly of colloidal particles in liquid crystals, by creating docking sites for a “lock-and-key” interaction. What happens when the liquid crystal prefers a distortion incompatible with the boundaries? Cholesteric liquid crystals have an intrinsic helical twist with a preferred periodicity. By studying cholesterics confined near undulated boundaries, we show that the interaction driving the lock-and-key assembly can be switched from attractive to repulsive. This makes it possible to selectively promote or inhibit particle trapping.
Boniello et al., Soft Matter 2019, 15, 5220
