Controlled Writhing of Chiral Matter in Deformable Droplet Confinement.

Chirality─the property of being nonsuperimposable on its mirror image─plays a fundamental role in shaping how materials interact with light, molecules, and external fields. This property is key to advancements in areas such as quantum computing, flexible electronics, and smart sensors. However, controlling chirality in materials beyond the molecular scale has remained a significant challenge. In this study, we demonstrate a new approach for controlling the chirality of self-assembled materials by manipulating their behavior within deformable emulsion droplets. These droplets, ranging from nanometers to micrometers in size, guide the twisting of chiral fibrils formed through molecular self-assembly, with the droplet size determining the chirality. Our results, based on over 20 different chiral molecules, show that droplet confinement can induce chirality inversion, where nanoscale and microscale droplets exhibit opposite handedness. When the size of the droplet matches the persistence length of the chiral fibrils, the particles form superhelical structures. If mismatched, the fibrils twist in the opposite direction. In addition, we show that surfactant-coated helical fibrils can elongate into micrometer-long structures via living self-assembly, with chirality dictated by the as-formed helical fibrils and not the additional monomers. This work paves the way for new strategies to design and control chiral materials with tailored properties for a range of cutting-edge applications.