Soft electrodes combining hydrogel and liquid metal

Soft Matter ◽  
2018 ◽  
Vol 14 (17) ◽  
pp. 3296-3303 ◽  
Author(s):  
Tim Shay ◽  
Orlin D. Velev ◽  
Michael D. Dickey

Liquid metals interfaced with hydrogels create soft, deformable electrodes for emerging wearable devices and soft robotics. This paper quantifies and tunes the impedance of this interface for use in ECG electrodes.

Soft Matter ◽  
2021 ◽  
Author(s):  
Najam Ul Hassan Shah ◽  
Wilson Kong ◽  
Nathan Casey ◽  
Shreyas Kanetkar ◽  
Robert Yue-Sheng Wang ◽  
...  

Gallium based liquid metals (LM) have prospective biomedical, stretchable electronics, soft robotics, and energy storage applications, and are being widely adopted as thermal interface materials. The danger of gallium corroding...


Author(s):  
Lucy Johnston ◽  
Jiong Yang ◽  
Jialuo Han ◽  
Kourosh Kalantar-Zadeh ◽  
Jianbo Tang

Liquid metals, highly conductive and flowable metals, are increasingly becoming versatile choices for soft electronics and wearable devices. High resolution liquid metal patterning strategies accommodative to different substrate materials and...


Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4250 ◽  
Author(s):  
Taeyeong Kim ◽  
Dong-min Kim ◽  
Bong Jae Lee ◽  
Jungchul Lee

Liquid metals are one of the most interesting and promising materials due to their electrical, fluidic, and thermophysical properties. With the aid of their exceptional deformable natures, liquid metals are now considered to be electrically conductive materials for sensors and actuators, major constituent transducers in soft robotics, that can experience and withstand significant levels of mechanical deformation. For the upcoming era of wearable electronics and soft robotics, we would like to offer an up-to-date overview of liquid metal-based soft (thus significantly deformable) sensors mainly but not limited to researchers in relevant fields. This paper will thoroughly highlight and critically review recent literature on design, fabrication, characterization, and application of liquid metal devices and suggest scientific and engineering routes towards liquid metal sensing devices of tomorrow.


Nanoscale ◽  
2021 ◽  
Author(s):  
Hiroki Ota ◽  
Nyamjargal Ochirkhuyag ◽  
Ryosuke Matsuda ◽  
Zihao Song ◽  
Fumika Nakamura ◽  
...  

Research on liquid metals has been steadily garnering more interest in recent times because the properties of these metals are conducive to flexible electronics applications; further, these metals are in...


Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4130
Author(s):  
Eric Rasmussen ◽  
Daniel Guo ◽  
Vybhav Murthy ◽  
Rachit Mishra ◽  
Cameron Riviere ◽  
...  

The field of soft robotics has attracted the interest of the medical community due to the ability of soft elastic materials to traverse the abnormal environment of the human body. However, sensing in soft robotics has been challenging due to the sensitivity of soft sensors to various loading conditions and the nonlinear signal responses that can arise under extreme loads. Ideally, soft sensors should provide a linear response under a specific loading condition and provide a different response for other loading directions. With these specifications in mind, our team created a soft elastomeric sensor designed to provide force feedback during cardiac catheter ablation surgery. Analytical and computational methods were explored to define a relationship between resistance and applied force for a semicircular, liquid metal filled channel in the soft elastomeric sensor. Pouillet’s Law is utilized to calculate the resistance based on the change in cross-sectional area resulting from various applied pressures. FEA simulations were created to simulate the deformation of the sensor under various loads. To confirm the validity of these simulations, the elastomer was modeled as a neo-Hookean material and the liquid metal was modeled as an incompressible fluid with negligible shear modulus under uniaxial compression. Results show a linearly proportional relationship between the resistance of the sensor and the application of a uniaxial force. Altering the direction of applied force results in a quadratic relationship between total resistance and the magnitude of force.


2013 ◽  
Vol 23 (2) ◽  
pp. 137-137 ◽  
Author(s):  
Vijay Sivan ◽  
Shi-Yang Tang ◽  
Anthony P. O'Mullane ◽  
Phred Petersen ◽  
Nicky Eshtiaghi ◽  
...  
Keyword(s):  

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kyuyoung Kim ◽  
Junseong Ahn ◽  
Yongrok Jeong ◽  
Jungrak Choi ◽  
Osman Gul ◽  
...  

AbstractElectronic skin (E-skin) capable of detecting various physical stimuli is required for monitoring external environments accurately. Here, we report an all-soft multiaxial force sensor based on liquid metal microchannel array for electronic skin applications. The proposed sensor is composed of stretchable elastomer and Galinstan, a eutectic gallium-indium alloy, providing a high mechanical flexibility and electro-mechanical durability. Liquid metal microchannel arrays are fabricated in multilayer and positioned along a dome structure to detect multi-directional forces, supported by numerical simulation results. By adjusting the height of the dome, we could control the response of the multiaxial sensor with respect to the deflection. As a demonstration of multiaxial force sensing, we were able to monitor the direction of multidirectional forces using a finger by the response of liquid metal microchannel arrays. This research could be applied to various fields including soft robotics, wearable devices, and smart prosthetics for artificial intelligent skin applications.


2007 ◽  
Vol 561-565 ◽  
pp. 1699-1701
Author(s):  
Nobuyuki Takahira ◽  
Takeshi Yoshikawa ◽  
Toshihiro Tanaka

Unusual wetting behavior of liquid Cu was found on a surface-oxidized iron substrate in reducing atmosphere. Liquid Cu wetted and spread very widely on the iron substrate when a droplet was attached with the substrate in Ar-10%H2 after the surface oxidation of the substrate. The oxidationreduction process fabricates a porous layer at the surface of the iron substrate. The pores in the porous iron layer are 3-dimensionally interconnected. Thus, liquid metals, which are contacted with the reduced iron samples, penetrate into these pores by capillary force to cause the unusual wetting behavior. It has been already confirmed that liquid Ag, Sn, In and Bi show this phenomenon onto surface-porous iron samples as well as liquid Cu. This unusual wetting behavior of a liquid metal has been correlated to the normal contact angle of the liquid metal on a flat iron substrate.


Author(s):  
A. Lipchitz ◽  
Lilian Laurent ◽  
G. D. Harvel

Several Generation IV nuclear reactors, such as sodium fast reactors and lead-bismuth fast reactors, use liquid metal as a coolant. In order to better understand and improve the thermal hydraulics of liquid metal cooled GEN IV nuclear reactors liquid metal flow needs to be studied in experimental circulation loops. Experimental circulation loops are often located in a laboratory setting. However, studying liquid metal two phase flow in laboratory settings can be difficult due to the high temperatures and safety hazards involved with traditional liquid metals such as sodium and lead-bismuth. One solution is to use a low melt metal alloy that is as benign as reasonably achievable. Field’s metal is a eutectic alloy of 51% Indium, 32.5% Bismuth and 16.5% Tin by weight and has a melting point of 335K making it ideal for use in a laboratory setting. A study is undertaken to determine its suitability to use in a two-phase experimental flow loop enhanced by magnetohydrodynamic forces. The study investigated its reactivity with air and water, its ability to be influenced by magnetic fields, its ability to flow, and its ease of manufacture. The experiments melted reference samples of Field’s metal and observed its behaviour in a glass beaker, submerged in water and an inclined stainless steel pipe. Then Field’s metal was manufactured in the laboratory and compared to the sample using the same set of experiments and standards. To determine Field’s metal degree of magnetism permanent neodymium magnets were used. Their strength was determined using a Gaussmeter. All experiments were recorded using a COHU digital camera. Image analysis was then performed on the video to determine any movements initiated by the magnetic field forces. In conclusion, Field’s metal is more than suitable for use in experimental settings as it is non-reactive, non-toxic, simple to manufacture, easy to use, and responds to a magnetic force.


2021 ◽  
Author(s):  
Guilin Liu ◽  
Jing Liu

Abstract The increasingly high power density of today's electronic devices requires the cooling techniques to produce highly effective heat dissipation performance with as little sacrifice as possible to the system compactness. Among the currently available thermal management schemes, the convective liquid metal cooling provides considerably high performance due to their unique thermal properties. This paper firstly reviews the studies on convective cooling using low-melting-point metals published in the past few decades. A group of equations for the thermophysical properties of In-Ga-Sn eutectic alloy is then documented by rigorous literature examination, following by a section of correlations for the heat transfer and flow resistance calculation to partially facilitate the designing work at the current stage. The urgent need to investigate the heat transfer and flow resistance of forced convection of low-melting-point metals in small/mini-channels, typical in compact electronic devices, is carefully argued. Some special aspects pertaining to the practical application of this cooling technique, including the entrance effect, mixed convection, and compact liquid metal heat exchanger design, are also discussed. Finally, future challenges and prospects are outlined.


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