Liquid–Liquid Encapsulation of Janus Drops

This study explores a novel approach that integrates in-air microfluidics with an impact-driven liquid-liquid encapsulation technique to achieve robust and efficient encapsulation of Janus droplets. The technique involves the generation of Janus droplets composed of two distinct core liquids using in-air microfluidics, which then impact a single interfacial layer floating on a host water bath, forming Janus-encapsulated cargos. The underlying dynamics of the liquid-liquid interfaces involved in encapsulating Janus droplets are captured using high-speed imaging. A nondimensional experimental regime is established for successful encapsulation in terms of the impact kinetic energy and the interfacial layer thickness. We demonstrate the versatility and robustness of this technique by varying the liquid used in the interfacial layer, illustrating its adaptability for diverse applications. Our findings highlight the simplicity and efficiency of this approach, offering a scalable and reproducible method for encapsulating Janus droplets. By optimizing interfacial properties and impact conditions, this technique holds promise for advancing the development of next-generation functional materials in biomedical, industrial, and environmental applications.