Particle-armored liquid robots.

It is challenging to emulate biological forms and functions with artificial machines: Fluidity and adaptability seen in cellular organisms, characterized by their ability to deform, split, merge, and engulf, are hard to recapitulate with traditional rigid robotic structures. A promising avenue to tackle this problem is harnessing the supreme deformability of liquids while providing stable yet flexible shells around them. Here, we report a highly robust liquid-particle composite, named a Particle-armored liquid roBot (PB), featuring a liquid blob coated with unusually abundant superhydrophobic particles. The enhanced deformability and structural stability of our millimetric PBs enable a range of versatile robotic functions, such as navigating through complex environments, engulfing and transporting cargoes, merging, and adapting to various environments. We use both theoretical analysis and experimental approaches to develop a framework for predicting the shape evolution, dynamics, and robotic functions of PBs. The forms and functions of our liquid robots mark an essential hallmark toward miniature biomachines that perform like cells.