Search

The artificial biomimetic sensory hair as state-of-art electronics has drawn great attention from academic theorists of industrial production given its potential application in soft robotics, environmental exploration and health monitoring. However, it still remains a challenge to develop highly sensitive electronic sensory hair with fast response. In this study, a bio-inspired electronic whisker (e-whisker) with a hollow polymer shell and a liquid metal core was prepared by microinjection for airflow measurement and detection of obstacles. In addition, we illustrated the effect of liquid metal hysteresis on its distribution in microchannels on deformation. The difference in the deformed velocity between the selected fiber and EGaIn would result in a disturbance emerging in the liquid metal channel, which further causes a variation in resistance. Taking advantage of this phenomenon, the integrated fiber e-whisker can be employed to detect tiny airflow and disturbance. The experimental results indicate that the fiber sensor can detect the airflow velocity as low as 0.2 m s

In this article, room temperature gallium-based fluids (RTGFs) with unique thermal and conductive properties are proposed as a transmission fluid for the force carrying medium of hydraulics, which rectify the lack of the multi-functional hydraulic roles of liquid metal (LM). The typical physical properties of RTGFs and comparative conventional hydraulic fluids (commercial hydraulic oil and deionized water), such as thermal stability and rheological characteristics are evaluated. Experimental and numerical methods, then, are adopted to clarify the force transmission performance of RTGFs and commercial hydraulic oils, as well as the influence of temperature fields on the viscosity of fluids. The results disclosed that the advantages of inherent flame resistance, wide liquid temperature range, and the viscosity changing slightly with temperature, make RTGFs potential to efficiently apply in the hydraulics as new working fluids. Finally, for illustration, the rigid and flexible actuators driven by RTGFs were designed as hydraulic fluid and demonstrated their capabilities in grasping objects with various shapes and weights, respectively. And the tunable stiffness of such a flexible actuator is enabled via the solid-liquid phase change of LM. Additionally, a frequency-adjustable antenna was manufactured and showcased owing to the introduced transformable electromagnetic behaviors of LM. Overall, the gallium-based LM fluids with thermoelectrical and mechanical multimodal signal medium, would serve as a potential candidate for future complex multifunctional signal transmission systems.

As as emerging innovation, electronic textiles have shown promising potential in health monitoring, energy harvesting, temperature regulation, and human-computer interactions. To access broader application scenarios, numerous e-textiles have been designed with a superhydrophobic surface to steer clear of interference from humidity or chemical decay. Nevertheless, even the cutting-edge electronic textiles (e-textiles) still have difficulty in realizing superior conductivity and satisfactory water repellency simultaneously. Herein, a facile and efficient approach to integrate a hierarchical elastic e-textile is proposed by electroless silver plating on GaIn alloy liquid metal coated textiles. The continuous uneven surface of AgNPs and deposition of FAS-17 endow the textile with exceptional and robust superhydrophobic performance, in which the conductivity and the contact angle of the as-made textile could reach 2145 ± 122 S/cm and 161.5 ± 2.1°, respectively. On the basis of such excellent conductivity, the electromagnetic interference (EMI) shielding function is excavated and the average shielding efficiency (SE) reaches about 87.56 dB within frequencies of 8.2-12.4 GHz. Furthermore, due to its high elasticity and low modulus, the textile can serve as a wearable strain sensor for motion detection, health monitoring, and underwater message transmission. This work provides a novel route to fabricate high-performance hydrophobic e-textiles, in which the encapsulation strategy could be referenced for the further development of conductive textiles.

BiInSn alloy, one of the low-melting-point alloys, has attracted more and more attention in various fields recently. However, research into applying BiInSn powder is limited, and most existing methods of preparing metal powders are not quite suitable for BiInSn alloy due to its special properties. Here, an effective method has been provided to fabricate BiInSn alloy powder based on ultrasonic crushing in combination with the dispersant solution. The effects of the dispersant and the cooling rate on the size distribution and shape of the powder are discussed. The experiment results show that the size of BiInSn powder prepared with ethylene glycol with higher viscosity is much smaller. Compared with bulk metal, the BiInSn powder exhibit more superior properties in the application. For example, the sintered BiInSn powder has better performance in the micro-hardness measurement. The micro-hardness of the products using ethylene glycol increases by 90.7% compared with that of the bulk metal. Besides, the BiInSn powder can be used to fabricate stretchable conductive material.

This study presents a U-shaped dual-frequency-reconfigurable liquid-metal monopole antenna. Eutectic Gallium–Indium (EGaIn) was used as a conductive fluid and filled in the two branches of the U-shaped glass tube. A precision syringe pump was connected to one of the branches of the U-shaped tube by a silicone tube to drive EGaIn, forming a height difference between the two liquid levels. When the height of liquid metal in the two branches met the initial condition of L1 = L2 = 10 mm, and L1 increased from 10 mm to 18 mm, the two branches obtained two working bandwidths of 2.27–4.98 GHz and 2.71–8.58 GHz, respectively. The maximum peak gain was 4.00 dBi. The initial amount of EGaIn also affected the available operating bandwidth. When the liquid metal was perfused according to the initial condition: L1 = L2 = 12 mm, and L1 was adjusted within the range of 12–20 mm, the two branches had the corresponding working bandwidths of 2.18–4.32 GHz and 2.57–9.09 GHz, and the measured maximum peak gain was 3.72 dBi. The simulation and measurement data corresponded well. A series of dual-frequency-reconfigurable antennas can be obtained by changing the initial amount of EGaIn. This series of antennas may have broad application prospects in fields such as base stations and navigation.

Hollow microspheres with high specific surface area are widely used in thermal insulation, drug delivery and sustained release, catalysis and optical absorption. Eutectic gallium-indium (EGaIn) undergoes phase transformation and oxidation when heated in aqueous solution, which can provide a crystal seed and preferential growth environment for nanomaterials. Therefore, it is very promising to further study the application of liquid metal in functional and structural nanomaterials. In this study, a EGaIn-based ice cream-shaped hollow sphere array with nanostructures was firstly synthesized on the designed hole array model using a hydrothermal process, and then the surface was further modified by fluorination to form a superhydrophobic film. Different sizes of the hollow Eutectic gallium-indium zinc oxide (EGaIn-ZnO) microspheres could be easily achieved by varying the size of the model, hence leading to controllable wettability. Furthermore, hollow microspheres hold much air, making it feasible for application in the field of anti-ice and thermal insulation.

This communication provides an integrated process route of smelting gallium-based liquid metal (GBLM) in a high vacuum, and injecting GBLM into the antenna channel in high-pressure protective gas, which avoids the oxidation of GBLM during smelting and filling. Then, a frequency-reconfigurable antenna, utilizing the thermal expansion characteristic of GBLM, is proposed. To drive GBLM into an air-proof space, the thermal expansion characteristics of GBLM are required. The dimensions of the radiating element of the liquid metal antenna can be adjusted at different temperatures, resulting in the reconfigurability of the operating frequency. To validate the proposed concept, an L-band antenna prototype was fabricated and measured. Experimental results demonstrate that the GBLM in the antenna was well filled, and the GBLM was not oxidized. Due to the GBLM being in an air-proof channel, the designed liquid metal antenna without electrolytes could be used in an air environment for a long time. The antenna is able to achieve an effective bandwidth of over 1.25–2.00 GHz between 25 °C and 100 °C. The maximum radiation efficiency and gain in the tunable range are 94% and 2.9 dBi, respectively. The designed antenna also provides a new approach to the fabrication of a temperature sensor that detects temperature in some situations that are challenging for conventional temperature sensing technology.

A one-step strategy for fabricating flexible conductors via phase separation is proposed, wherein, the liquid metal was implanted into polydimethylsiloxane, whose viscosity was changed using hexane. Such self-encapsulating composite exhibited good electronic and mechanical stability under mechanical cycles with no significant leaking of droplets during the testing process.

The GaIn based room temperature liquid metal (LM) is a potential material for sensing applications due to its good fluidity and excellent conductivity. The change in volume or shape substantially modifies the LM electrical properties, especially in the case of limited volume. In this study, we coated LM on fiber arrays to establish a relationship between external stress and the electrical signal. The external force applied to the flexible fibers induces their deformation, changing the electrical signal. We recorded this change experimentally and established the relationship between the stress and the electrical signal. The sensitivity can be adjusted by the elastic module and length of fibers. Fiber arrays of different lengths may cover a wide range of stress values. This novel design has potential applications in the fields of sensing and stretchable electronics.