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Crystallization of alloys from a molten state is a fundamental process underpinning metallurgy. Here the direct imaging of an intermetallic precipitation reaction at equilibrium in a liquid‐metal environment is demonstrated. It is shown that the outer layers of a solidified intermetallic are surprisingly unstable to the depths of several nanometers, fluctuating between a crystalline and a liquid state. This effect, referred to herein as crystal interface liquefaction, is observed at remarkably low temperatures and results in highly unstable crystal interfaces at temperatures exceeding 200 K below the bulk melting point of the solid. In general, any liquefaction process would occur at or close to the formal melting point of a solid, thus differentiating the observed liquefaction phenomenon from other processes such as surface pre‐melting or conventional bulk melting. Crystal interface liquefaction is observed in a variety of binary alloy systems and as such, the findings may impact the understanding of crystallization and solidification processes in metallic systems and alloys more generally. [ABSTRACT FROM AUTHOR]

Heavy metal ions contamination is an ever‐growing threat to human health and ecosystems. Analytic sensing of heavy metal ions is a prerequisite step toward addressing this challenge. Electroanalytical technique is an effective and convenient way to detect heavy metal ions. Especially, stripping voltammetry techniques have been utilized for sensing metal ions at trace levels in different sample matrices. The choice of the working electrode materials plays a decisive role in the precision and sensitivity of stripping voltammetry. Post‐transition metals (including elements in group 12) are elements with low melting points, demonstrating unique properties including amalgamation with heavy metal ions that enhance the performance of stripping voltammetry during the pre‐concentration step, which make them particularly suitable for heavy metal ion sensing. Here, for better understanding the features and advantages of post‐transition metals in stripping voltammetry, eight classes of working electrodes based on zinc (Zn), mercury (Hg), gallium (Ga), indium (In), tin (Sn), lead (Pb), antimony (Sb), and bismuth (Bi), are reviewed, with their efficiency and effectiveness compared and recent progresses discussed. Additionally, liquid metal electrodes based on post‐transition metals and alloys are also presented. This review provides viable directions for future development of heavy metal ion sensors based on post‐transition metals. [ABSTRACT FROM AUTHOR]

This study focuses on the influence of driving fluid properties on the mass transfer process of ejector apparatus. A liquid-actuated ejector system is firstly designed and three experimental cases working with different kinds of driving fluids, i.e., gallium-based liquid metal, aqueous NaI solution and water, are successively investigated. The results show that the ejector system working with liquid metal has high-vacuum ejecting capacity and good temperature stability. With a system power consumption of about 50 W, the liquid metal driving ejector obtains a no-entrainment vacuum pressure of 33 Pa which is three orders of magnitudes lower than that of the water driving case. When the gas-suction pressure exceeds 40 kPa, NaI solution driving case reveals the highest entrainment. The reasons for the differences in the ejector performance are later discussed. Based on the experimental results and theoretical analyses, the method of using high density, low viscosity and low vapor pressure working fluid to improve ejector performance is proposed. Other than conventional methods which focus on optimizing the geometrical design and operating parameters of ejectors, the method discussed here puts forward a new perspective to improve ejector performance. Moreover, the ejector system working with liquid metal demonstrates its advantages such as compact system design, oil-free vacuum pumping as well as high temperature operation. [ABSTRACT FROM AUTHOR]

As soft conductive materials with high liquid fluidity, the room‐temperature liquid metal alloys (LMs) offer a superior alternative to the fabrication of flexible electronics. So far, techniques aiming at patterning LMs are seriously limited by the alloy's high surface tension and poor wettability with many substrates. Additionally, LMs based mass production with fast and efficient printing on desired target still encounters tremendous unsolved challenges. Here, a one‐step liquid metal transfer printing method with wide range substrate adaptability, comprising of polymer‐based adhesive glue, its printing machine, the LMs ink, and the soft substrate is presented. It is demonstrated that even on those substrates with weak wettability to LMs, the liquid metal transfer printing still works well to create complex conductive geometries, multilayer circuits, and large‐area conductive patterns with excellent transfer efficiency, facile fabrication process, and remarkable electrical stability, which is beneficial to quickly construct wearable electronics, 3D folding conductive structures, flexible actuators, soft robots, etc. Moreover, its advantages of self‐healing and recyclable ability make the strategy possible to prepare reconfigurable circuits and further reduce the cost of fabrication and environmental pollution. This study suggests an important way for future widespread practices of liquid metal soft functional electronics. A one‐step liquid metal transfer printing method for flexible electronics based on adhesion difference of EGaIn on allied substrates is developed. The EGaIn could be adhered to polymethacrylates glue, but not paper. This fabrication method has five advantages: (1) fast fabrication; (2) excellent electrical stability; (3) simple to fabricate multilayer and large‐area circuits; (4) self‐healing ability; (5) reversion of EGaIn. [ABSTRACT FROM AUTHOR]

In article number 1800265, Rui Gao, Jing Liu, Wei Rao, and co‐workers demonstrate a new kind of one‐step liquid metal transfer printing method with rather wide range substrate adaptability. As illustrated here, a classical Chinese ancient painting (Riverside Scene on Pure Brightness Festival) was thus printed on a picture scroll. With preprinted glue, liquid metal can be selectively patterned on target substrate such as paper to compose various flexible functional electronics. [ABSTRACT FROM AUTHOR]

Gallium and many of its alloys remain in liquid phase across impressively wide temperature ranges. Here such liquid metals are proposed as reaction media for the carbonization of low thermal stability polymeric precursors at high temperatures. Plain and cross-linked polyvinyl alcohol are chosen as representatives of such polymers. We show that due to the immiscibility of organic carbons within the liquid metal phase, these polymers that would otherwise vaporize at elevated temperatures, can function as precursors for the formation of carbonaceous films. The thin polymeric films are placed in an intimate contact with the liquid metal surface before thermal processing and show amorphous to graphitic-like characteristics after carbonization. Graphitic-like properties were obtained when a high melting point graphitization catalyst, such as copper, was co-alloyed. The proposed work can be expanded to explore other metallic elements within the bulk of gallium-based alloys for the carbonization of polymeric precursors at large-scales. Image 1 • Polymers that do not carbonize otherwise can be 'capped' by liquid metals and thereby carbonized. • Gallium-based liquid metals exhibit selective miscibility to non-metallic elements. • Gallium, gallium-indium and gallium-copper were chosen as liquid metal reactors. • Carbon films with amorphous and graphitic characteristics were formed. • Inclusion of copper in liquid metal enhanced the graphitic characteristics of the films. [ABSTRACT FROM AUTHOR]