Smart Eutectic Gallium–Indium: From Properties to Applications

Abstract

Eutectic gallium–indium (EGaIn), a liquid metal with a melting point close to or below room temperature, has attracted extensive attention in recent years due to its excellent properties such as fluidity, high conductivity, thermal conductivity, stretchability, self‐healing capability, biocompatibility, and recyclability. These features of EGaIn can be adjusted by changing the experimental condition, and various composite materials with extended properties can be further obtained by mixing EGaIn with other materials. In this review, not only the are unique properties of EGaIn introduced, but also the working principles for the EGaIn‐based devices are illustrated and the developments of EGaIn‐related techniques are summarized. The applications of EGaIn in various fields, such as flexible electronics (sensors, antennas, electronic circuits), molecular electronics (molecular memory, opto‐electronic switches, or reconfigurable junctions), energy catalysis (heat management, motors, generators, batteries), biomedical science (drug delivery, tumor therapy, bioimaging and neural interfaces) are reviewed. Finally, a critical discussion of the main challenges for the development of EGaIn‐based techniques are discussed, and the potential applications in new fields are prospected.

Estimating the Number of Molecules in Molecular Junctions Merely Based on the Low Bias Tunneling Conductance at Variable Temperature

“…The former includes mechanically controllable break junctions (MCBJ) [ 7 , 8 ] and scanning tunneling microscopy (STM) break junctions [ 9 , 10 , 11 , 12 ] as well as electromigration [ 13 , 14 , 15 ] platforms. Conducting probe atomic force microscopy (CP-AFM) [ 16 , 17 , 18 , 19 , 20 ], cross-wires [ 21 , 22 , 23 , 24 , 25 ] and large area liquid metal (eutectic gallium indium alloy EGaIn) based molecular junctions [ 15 , 26 , 27 , 28 ] are examples of the second category. For the latter, the key role played by the number of molecules and the related effective contact area has been thoroughly emphasized in the literature [ 5 , 26 , 29 ].…”

Highly Stable Liquid Metal Conductors with Superior Electrical Stability and Tough Interface Bonding for Stretchable Electronics

“…However, for the sample by direct writing, the interface is a remarkable plane between the LM and the substrate (Figure b). The presence of the oxide layer tends to adhere to many different substrate surfaces, resulting in solid–solid contact between the LM and the solid substrate and providing strong adhesion. , Additionally, the area of LM could be significantly increased by breaking it into small droplets . After the polymer is poured onto the LMPs, more oxide layers are in contact with the polymer substrate, thereby enhancing the adhesive strength by increasing the contact area between the LM and the polymer …”

Advancement in Soft Iontronic Resistive Memory Devices and Their Application for Neuromorphic Computing

“…[153] With its metallic core and soft, flexible shape, EGaln can be used in soft robots, wearable electrical devices, and liquid electrodes, all of which have a major impact on the future of technology. [153,154] EGaln liquid metal is also being investigated as a soft and liquid electrode for resistive memory devices.…”