Active transformations of topological structures in light-driven nematic disclination networks

Topological structures, such as topological defects, solitons, and vortices, are key to understanding the collective dynamics and spontaneous flows in active soft matter and are thereby important for their further applications. However, it is challenging to manipulate these topological structures in active matter due to their nonequilibrium nature. Here, we show that we can use light irradiation to trigger programmable transformations of topological structures in a predesigned disclination network. Specifically, we introduced topological patterns to a surface to frustrate the infiltrated nematic liquid crystal, giving rise to a three-dimensional disclination network with designated topological structures. These networks can be driven out of equilibrium by light irradiation and undergo a series of dynamic events, ending in different defect structures. The spatiotemporal evolutions of light-driven topological excitations in the form of disclination lines and loops are well characterized by continuum simulations. By dispersing nematic with amphiphilic molecules, we demonstrate a simultaneous transformation of disclination-guided, molecular self-assembly patterns. The demonstrated capability of commanding the topological transformation of defects using light opens opportunities for designing smart active materials.