Liquid-Liquid Interfaces and Grain Boundaries Engineering of Soft Crystals

In solid state science, a considerable challenge remains in the development of techniques toward grain-boundary engineering, which is fundamental for designing materials with specific mechanical properties. Meanwhile, in soft matter a significant number of natural phenomena take place at liquid-liquid interfaces. Similar to grain boundaries of solid crystals, liquid-liquid interfaces lack of shape control, placing limits to applications in biosensing, photonics, directed self-assembly and adsorption phenomena. In this work, we build on soft-matter heteroepitaxy to grow, not solids, but single crystals of cubic liquid-crystalline BPs. Specifically, we rely on accurately designed binary-anchoring patterned substrates that facilitate spontaneous BP nucleation over the whole patterned region. This leads to a distortion-free BP-soft crystal, with a uniform lattice orientation that depends on the symmetry of the pattern used. Based on such liquid-liquid interfacial behavior, we produce large, stable and single-crystal BP-domains can serve as an alternative for engineering materials with accurately localized regions that respond sensitively to contaminants, incident light, electric or magnetic fields and other external stimuli.