Hydrogel bioelectronics that can interface biological tissues and flexible electronics is at the core of the growing field of healthcare monitoring, smart drug systems, and wearable and implantable devices. Here, a simple strategy is demonstrated to prototype all‐hydrogel bioelectronics with embedded arbitrary conductive networks using tough hydrogels and liquid metal. Due to their excellent stretchability, the resultant all‐hydrogel bioelectronics exhibits stable electrochemical properties at large tensile stretch and various modes of deformation. The potential of fabricated all‐hydrogel bioelectronics is demonstrated as wearable strain sensors, cardiac patches, and near‐field communication (NFC) devices for monitoring various physiological conditions wirelessly. The presented simple platform paves the way of implantable hydrogel electronics for Internet‐of‐Things and tissue–machine interfacing applications.

Understanding the mechanical stability of granular‐armored liquid marbles is prerequisite for their applications including encapsulation, sensors, microreactions, and miniaturized liquid storage. Most liquid marbles are armored with agglomerated granular structure which complicates the wetting and interacting states of particles, hence, impeding one from understanding the effect of granular size on the mechanical stability of marbles. In this work, using a custom‐built platform to examine the liquid marbles armored by a single layer of uniform grains, it is revealed that larger microsized grains produce stronger liquid marble. This finding is attributed to the gravity‐induced capillary attraction which dominates the interaction of particles and provides additional tension to the granular network of the marble surface, which enhances the mechanical stability of marbles. In addition, different granular network structures are formed at the marble surface by using a binary mixture of monodisperse grains, and their effect on the mechanical stability of marbles is explored. The understandings offer important insights for application involving liquid marbles and provides guideline to formulate robust marble‐based products.

Miniaturized droplet reactors hold great promise for the development of green and sustainable chemistry. However, handling liquids with small volumes, especially viscous ones, in a convenient and loss-free manner remains a challenge. Here, by electrically controlling the coalescence and mixing of particle-coated droplets, also known as liquid marbles, an effective micro reactor is demonstrated for miniaturized chemical reactions involving viscous reagents. By applying an electric voltage to marbles, the induced electromixing of marble microreactors promotes the reaction rate and the product yield. The advantages of electromixed marble reactors are manifested by a series of chemical reactions between aldehydes and 2-methylindole in viscous glycerol solution. The electrically-controlled coalescence and mixing establish liquid marbles as microreactors for rapid, efficient, and miniaturized chemical reactions.

An improved understanding of the rupture dynamics for liquid marbles is essential for their application in sensors, miniaturized reactions, biomedical scaffolds, the synthesis of functional materials, and others. This work suggests that a compressed liquid marble always ruptures at the edge of the contact area between the marble and a substrate. The rupture dynamics of a compressed marble is visualized with a particle-level resolution using a marble coated with monodispersed microparticles. High-speed photography indicates that the particle density decreases significantly from the center to the edge, and the sparse particle layer at the edge initiates rupturing. Such a particle density distribution is well depicted with our proposed model, which predicts the theoretical values that agree well with the experimental results. This study generalizes the understanding for the rupture dynamics of particle-stabilized droplets and is beneficial to any applications that involve the rupture or coalescence of liquid marbles as well as Pickering emulsions.

We present an ultra-stretchable all-hydrogel electronic device with microfluidic patterns perfused with ionic liquids for skin-conformed sensing under large stretches.