This review discusses the opportunities provided by gallium liquid metal alloys for making various microfluidic components.

Small-scale pumps will be the heartbeat of many future micro/nanoscale platforms. However, integration small-scale is presently hampered by limited flow rate with respect to input power, and their rather complicated fabrication processes. These issues arise as conventional pumping effects require intricate moving elements. Here, we demonstrate a system that call liquid metal enabled pump, for driving range liquids without mechanical parts, upon application modest electric field. This pump...

Abstract Conductive elastic composites have been used widely in soft electronics and robotics. These are typically a mixture of conductive fillers within elastomeric substrates. They can sense strain via changes resistance resulting from separation the during elongation. Thus, most exhibit negative piezoconductive effect, i.e. conductivity decreases under tensile strain. This property is undesirable for stretchable conductors since such may become less deformation. Here, we report liquid...

Abstract Liquid metal marbles that are droplets of liquid encapsulated by micro‐ or nanoparticles introduced. Droplets galinstan coated with insulators (including Teflon and silica) semiconductors WO 3 , TiO 2, MoO In 2 O carbon nanotubes) rolling over a powder bed also submerging in colloidal suspensions. It is shown these can be split merged, suspended on water, even stable when moving under the force gravity impacting flat solid surface. Furthermore, marble coating operate as an active...

Quasi-two-dimensional (quasi-2D) molybdenum disulfide (MoS2) is a photoluminescence (PL) material with unique properties. The recent demonstration of its PL, controlled by the intercalation positive ions, can lead to many opportunities for employing this quasi-2D in ion-related biological applications. Here, we present two representative models systems that incorporate ion-controlled PL MoS2 nanoflakes. ion exchange behaviors these are investigated reveal enzymatic activities and cell...

Controlled actuation of soft objects with functional surfaces in aqueous environments presents opportunities for liquid phase electronics, novel assembled super-structures and unusual mechanical properties. We show the extraordinary electrochemically induced metal droplets coated nanoparticles, so-called “liquid marbles”. demonstrate that nanoparticle coatings these marbles offer an extra dimension affecting bipolar actuation. The nanoparticles can readily migrate along surface metals, upon...

A new platform described as the liquid metal/metal oxide (LM/MO) framework is introduced. The constituent spherical structures of these frameworks are made micro‐ to nanosized metal spheres and oxides, combining advantages both materials. It shown that diameters stoichiometry can be actively controlled. Additionally, suspension demonstrates tuneable plasmon resonances. These assembled form LM/MO which capable demonstrating high sensitivity towards low concentrations heavy ions, enhanced...

Gallium is a metal that literally melts in your hand. It has low toxicity, near-zero vapor pressure, and viscosity similar to water. Despite possessing surface tension larger than any other liquid (near room temperature), gallium can form nonspherical shapes due the thin, solid native oxide skin forms rapidly oxygen. These properties enable new ways pattern metals (e.g., injection printing) create stretchable soft devices with an unmatched combination of mechanical electrical properties. The...

Chaotic advection plays an important role in microplatforms for a variety of applications. Currently used mechanisms inducing chaotic small scale, however, are limited by their complicated fabrication processes and relatively high power consumption. Here, soft actuator is reported which utilizes droplet Galinstan liquid metal to induce harmonic Marangoni flow at the surface when activated sinusoidal signal. This has no rigid parts employs continuous electrowetting effect with exceptionally...

Significance Single-cell biology requires the ability to construct experiments with single-cell precision, large numbers, and extremely small fluid volumes. To address this need, we have developed a new technology, printed droplet microfluidics, which encapsulates reagents single cells in picoliter droplets, then actively selects deposits desired droplets an arrayed format on printing substrate. This technology enables construction of number relevant single-cellular multicellular methods detection.

Abstract Artificial muscles possess a vast potential in accelerating the development of robotics, exoskeletons, and prosthetics. Although variety emerging actuator technologies are reported, they suffer from several issues, such as high driving voltages, large hysteresis, water intolerance. Here, liquid metal artificial muscle (LMAM) is demonstrated, based on electrochemically tunable interfacial tension to mimic contraction extension muscles. The LMAM can work different solutions with wide...

Stretchable conductive composites (SCCs) are generally elastomer matrices filled with fillers. They combine the conductivity of metals and carbon materials flexibility polymers, which attractive properties for applications such as stretchable electronics, wearable devices, flexible sensors. Most conventional that only one type filler face issues in mechanical electrical properties. Recently, some studies introduced secondary fillers to create hybrid‐filler SCCs solve these problems. The...

Abstract 4D printing combines 3D with nanomaterials to create shape-morphing materials that exhibit stimuli-responsive functionalities. In this study, reversible addition-fragmentation chain transfer polymerization agents grafted onto liquid metal nanoparticles are successfully employed in ultraviolet light-mediated stereolithographic and near-infrared light-responsive printing. Spherical directly prepared 3D-printed resins via a one-pot approach, providing simple efficient strategy for...

We demonstrate photochemically induced actuation of liquid metal marbles, which are droplets encased in micro/nanoparticles. The WO3 nanoparticles coated marbles placed H2O2 solution, and their surfaces illuminated with UV light. semiconducting coating behaves as a photocatalyst to trigger photochemical reaction, generating oxygen bubbles that propel the marble. is investigated under different concentrations, light intensities, marble dimensions. Equations describing fundamentals such...

Solvothermally synthesized Ga2O3 nanoparticles are incorporated into liquid metal/metal oxide (LM/MO) frameworks in order to form enhanced photocatalytic systems. The LM/MO frameworks, both with and without nanoparticles, show activity due a plasmonic effect where performance is related the loading of nanoparticles. Optimum efficiency obtained 1 wt % incorporation This can be attributed sub-bandgap states contributing pseudo-ohmic contacts which reduce free carrier injection barrier Ga2O3.

Abstract Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields flexible electronics, sensors, catalysts, drug delivery systems. Methods used currently for producing metal have significant disadvantages they rely on both bulky expensive high‐power sonication probe systems, also generally require use small molecules bearing thiol groups to stabilize nanoparticles. Herein, an innovative...

The controlled actuation of gallium liquid-metal (LM) alloys has presented new and exciting opportunities for constructing mobile robots with structural flexibility. However, the locomotion current LM-based actuators often relies on inducing a gradient interfacial tension LM surface within electrolytes, which limits their application outside liquid environment. In this work, wheeled robot using droplet as core driving system is developed that enables it to move inside actuated voltage alter...

Liquid metal co-injected with electrolyte through a microfluidic flow-focusing orifice forms droplets diameters and production frequencies controlled in real time by voltage. Applying voltage to the liquid controls interfacial tension via combination of electrochemistry electrocapillarity. This simple effective method can instantaneously tune size microdroplets, which has applications composites, catalysts, microsystems.

The continued miniaturization of electronic components demands integrated liquid cooling systems with minimized external connections and fabrication costs that can be implanted very close to localized hot spots. This might challenging for existing because most them rely on pumps, connecting tubes, microfabricated heat sinks. Here, we demonstrate an system by utilizing a small droplet metal Galinstan, which is placed over the spot. Energizing square wave signal creates surface tension...

We demonstrate sonication-enabled production of liquid metal nanoparticles grafted with poly(1-octadecene-<italic>alt</italic>-maleic anhydride) in water that remain stable biological buffers.