Sculpted grain boundaries in soft crystals

Engineering the grain boundaries of crystalline materials represents an enduring challenge, particularly in the case of soft materials. Grain boundaries, however, can provide preferential sites for chemical reactions, adsorption processes, nucleation of phase transitions, and mechanical transformations. In this work, soft heteroepitaxy is used to exert precise control over the lattice orientation of three-dimensional liquid crystalline soft crystals, thereby granting the ability to sculpt the grain boundaries between them. Since these soft crystals are liquid-like in nature, the heteroepitaxy approach introduced here provides a clear strategy to accurately mold liquid-liquid interfaces in structured liquids with a hitherto unavailable level of precision.