The appeal of liquid metals begins with a basic physical paradox. Conventional stretchable conductors rely on rigid fillers, such as silver flakes or carbon particles, embedded in an elastic matrix. Increasing the filler loading improves conductivity but stiffens the composite and accelerates fatigue under repeated strain; reducing the loading preserves softness but degrades electrical performance. This conductivity–softness trade-off has constrained generations of wearable and implantable devices. Liquid metals, most notably eutectic gallium–indium alloys that remain molten at room temperature, sidestep the problem entirely because the conductive phase is itself a fluid. Droplets of the alloy can be suspended in elastomers, where they deform, elongate and reconfigure with the surrounding polymer rather than resisting it, maintaining metallic properties across large strains.

The review emphasizes that liquid metal composites deliver far more than stretchable wiring. When droplets are dispersed through a soft polymer, they enhance not only electrical conductivity but also dielectric and thermal properties. Elongated liquid metal inclusions, for example, have been shown to raise the thermal conductivity of elastomers dramatically, enabling soft materials that can dissipate heat, and liquid metal inclusions have been used to create high-permittivity dielectric elastomers for capacitive and actuating applications. In one striking demonstration highlighted in the review, an electrically insulating liquid metal silicone compound combined electromagnetic interference shielding with direct electronic potting and thermal management, showing that a single soft composite can perform multiple functions once reserved for rigid metal housings.

Yet the same fluidity that gives liquid metals their conformability creates their greatest engineering headaches. A liquid conductor can leak, smear, delaminate or migrate within a device, destroying pattern fidelity and reliability. The authors argue that the decisive design variable is not the liquid metal itself but the interfaces it forms, both between liquid metal and the surrounding polymer and between liquid metal inks and the substrates and components they must connect. Interface engineering, they contend, is essential for mitigating leakage, delamination and functional degradation under deformation, and tailored interfacial design is what converts a promising ink into a robust, integrated device.

A rich toolkit of surface chemistry has emerged to control these interfaces. Gallium-based alloys spontaneously form a thin native oxide skin that dramatically alters their interfacial energy, lowering surface tension enough to allow the metal to be shaped, printed and stabilized as droplets. Researchers have exploited this oxide, and chemical modifications of it, to stabilize particles, tune wettability and promote adhesion. Polyphenol-induced adhesives have produced liquid metal inks that write directly on nearly any substrate, while thiol coordination chemistry has been used to soften liquid metal particles and switch their conductivity on demand. Hydrogen-doped viscoplastic microparticles have enabled stretchable printed metal lines, and finite-gel strategies have produced highly concentrated inks suitable for direct writing.

Patterning at high resolution remains one of the field’s defining challenges, and the review surveys how recent advances in droplet stabilization and ink formulation are addressing it. Ultrasonic sintering has been used to assemble liquid metal particles within polymers into elastic printed circuit boards, in which pressing or sonicating the particles ruptures their oxide shells and merges them into continuous, leakage-resistant traces. Laser sintering of liquid metal nanoparticles offers a scalable route to soft, flexible electronics, and projection lithography has enabled rapid printing of highly stretchable circuits. Meniscus-guided printing has produced stable semi-solid microgranular particles for soft electronics, while high internal phase emulsion inks have allowed direct-ink-writing of three-dimensional liquid metal structures. One recent metalgel formulation maintained a conductivity of three million siemens per metre through a million stretching cycles, a durability benchmark that would have seemed unattainable for a fluid conductor only a decade ago.

The applications catalogued in the review span the full breadth of soft electronics. In wearable healthcare, liquid metal electrodes and sensors have been fashioned into electronic tattoos, electromyography patches for tendon localization and muscle injury prevention, and pressure sensors for health monitoring. In implantable and bioelectronic systems, liquid metal microelectrodes have been wafer-patterned for chronic biocompatibility, printed directly on the cranium for soft neural probes, and formed into three-dimensional microelectrode arrays integrated with ultrathin retinal prostheses for vision restoration; liquid metal neuro-interfaces have even been used to stimulate and record from human hippocampal organoids. Phase-transition behavior adds another dimension: temperature-responsive intravenous needles that irreversibly soften on insertion, and biphasic microfibers for minimally invasive implantable electronics, exploit alloys that are rigid at room temperature and compliant at body temperature.

Soft robotics and integrated systems feature prominently as well. Liquid metal–elastomer composites have demonstrated autonomous electrical self-healing, in which damaged circuits reconnect themselves as the liquid metal flows back together, and liquid metal inclusions have enabled shape-morphing elastomers that couple thermal transport with programmable actuation. Stretchable Arduinos embedded in soft robots, octopus-inspired sensorized arms, and stretchable core–shell cables that are patternable, recyclable and noise-resistant all illustrate how liquid metals can bridge soft and rigid electronic domains. Liquid crystal elastomer composites actuated by induction heating point toward untethered, programmable soft machines, while liquid metal antennas exploit fluidic deformability for reconfigurable radio-frequency devices.

The authors are candid about what stands between laboratory demonstrations and real-world deployment. Long-term interface durability and manufacturing precision remain the key translation challenges: devices must survive millions of deformation cycles in wet, biological environments without leaking, delaminating or drifting in performance, and patterning methods must reach the resolution and throughput that industrial electronics demand. Questions of biocompatibility are being actively studied, with gallium’s known antimicrobial activity offering intriguing therapeutic possibilities even as toxicity profiles continue to be mapped. The review’s central message is nonetheless one of momentum: by treating the liquid metal–material interface as the primary design object, rather than an afterthought, researchers now have a coherent strategy for building soft electronics that no longer force a choice between how well a device performs and how gracefully it bends. If that strategy matures, the circuits of the future may not merely sit on the body but move with it, heal with it and, in the case of implants, dissolve the boundary between machine and tissue altogether.

Subject of Research: Design strategies for liquid metal-based soft and stretchable electronics

Article Title: Design strategies for liquid metal-based soft electronics

Article References: Pan, C., Zhang, C., Wang, J., Han, M., CHIU, W. Y. P., Zhao, P., & Dickey, M. D. (2026). Design strategies for liquid metal-based soft electronics. Nature Reviews Electrical Engineering. https://doi.org/10.1038/s44287-026-00335-1

Image Credits: AI Generated

DOI: 10.1038/s44287-026-00335-1

Keywords: liquid metals, stretchable electronics, soft electronics, gallium alloys, interface engineering, wearable devices, implantable bioelectronics, soft robotics, elastomer composites, self-healing materials, printed electronics, dielectric elastomers