Interface structure of the dark conglomerate liquid crystal phase

Abstract

The dark conglomerate (DC) phase is the spontaneously chiral, isotropic fluid formed by achiral bent-core liquid crystal molecules characterized by well-defined local smectic liquid crystal layering deformed into a disordered “plumber's nightmare” array of 100 nm-scale, focal conic-like domains. Here we report the interface structure of this phase, showing that surface confinement orders the focal conics into a hexagonal plumber's nightmare lattice, directly confirming the topology proposed for the DC phase. The observations suggest that a bulk phase of saddle–splay dominated focal conics may be produced in DC materials under suitable conditions, which opens the way for the development of two-dimensional or even three-dimensional periodic dielectric media for photonic crystal applications.