Flexible Electronics: Towards Sub-Microscale Liquid Metal Patterns: Cascade Phase Change Mediated Pick-n-Place Transfer of Liquid Metals Printed and Stretched over a Flexible Substrate (Adv. Funct. Mater. 28/2018)

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...

Download Full-text

Is There a Relationship between Surface Wettability of Structured Surfaces and Lyophobicity toward Liquid Metals?

Materials ◽

10.3390/ma13102283 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2283 ◽

Cited By ~ 2

Author(s):

Stephan Handschuh-Wang ◽

Lifei Zhu ◽

Tao Wang

Keyword(s):

Liquid Metal ◽

Flexible Electronics ◽

Liquid Metals ◽

Metal Layer ◽

Surface Wettability ◽

Diamond Coating ◽

Air Plasma ◽

Structured Surfaces ◽

Static Contact ◽

The Impact

The liquid metal lyophobicity of a rough substrate was, in previous articles, found to be rather independent on the surface wettability. In this article, we scrutinize the impact of surface wettability of a structured (rough) surface on the liquid metal wettability and adhesion. As a model system, a structured diamond coating was synthesized and modified by air plasma. We show that surface wettability (surface free energy) does not play a prominent role for static contact angle measurements and for the liquid metal repelling properties of the diamond coating in droplet impact experiments. In contrast, roll off angles and repeated deposition experiments illustrate that the increased hydrophilicity impacts the long-term liquid metal repellency of our coating. Liquid metal adhered after around 50 deposition/removal cycles on the hydrophilic diamond coating, while no liquid metal adhesion was visible after 100 cycles on the hydrophobic diamond coating, illustrating the fundamental role for the adhesion of liquid metal. The effect of repeated deposition in conjunction with gentle applied force was employed for coating the liquid metal lyophobic (hydrophilic) diamond coating with a thin liquid metal layer. The observed effect may find application in flexible electronics and thermal management systems as a means to improve interfacing of the liquid metal with conductive non-metal coatings.

Download Full-text

Low-Cost Rapid Fabrication of Conformal Liquid-Metal Patterns

Applied Sciences ◽

10.3390/app9081565 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1565 ◽

Cited By ~ 3

Author(s):

Elassy ◽

Akau ◽

Shiroma ◽

Seo ◽

Ohta

Keyword(s):

Liquid Metal ◽

Flexible Electronics ◽

Communication Systems ◽

Liquid Metals ◽

Low Cost ◽

Spray Coating ◽

Uv Curable ◽

Rapid Fabrication ◽

Communication Devices ◽

Stretchable Conductors

Patterned conformal conductive structures are used to realize flexible electronics for applications such as electronic skin, communication devices, and sensors. Thus, there is a demand for low-cost rapid fabrication techniques for flexible and stretchable conductors. Spray-coating of liquid metals is a prototyping method that is compatible with elastic substrates. In this work, UV-curable and polyimide masks were used to pattern sprayed liquid metal (LM). The effect of the spraying parameters on the thickness and conductivity of the LM was characterized. A minimum LM linewidth of 48 µm was achieved, along with a minimum gap width of 34 µm. A LM patch antenna and transmission line, which can potentially be used for communication systems, were demonstrated using this fabrication process.

Download Full-text

Intermetallic wetting enabled high resolution liquid metal patterning for 3D and flexible electronics

Journal of Materials Chemistry C ◽

10.1039/d1tc04877e ◽

2022 ◽

Author(s):

Lucy Johnston ◽

Jiong Yang ◽

Jialuo Han ◽

Kourosh Kalantar-Zadeh ◽

Jianbo Tang

Keyword(s):

High Resolution ◽

Liquid Metal ◽

Flexible Electronics ◽

Liquid Metals ◽

Wearable Devices ◽

Soft Electronics

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...

Download Full-text

NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

Fourth International Topical Meeting on High Temperature Reactor Technology, Volume 1 ◽

10.1115/htr2008-58197 ◽

2008 ◽

Cited By ~ 4

Author(s):

Piyush Sabharwall ◽

Mike Patterson ◽

Vivek Utgikar ◽

Fred Gunnerson

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchange ◽

Pressure Drop ◽

Liquid Metal ◽

Phase Change ◽

Heat Exchangers ◽

Liquid Metals ◽

Compact Heat Exchangers ◽

Process Heat

One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor-process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rationale for considering liquid metals as the working fluid is because of the higher convective heat transfer coefficient. This explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet of NGNP and inlet of the process heat facility. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change heat exchanger with Na as the heat exchanger coolant. In order to design a very efficient and effective heat exchanger one must optimize the design such that we have a high heat transfer and a lower pressure drop, but there is always a tradeoff between them. Based on NGNP operational parameters, a heat exchanger analysis with the sodium phase change is presented to show that the heat exchanger has the potential for highly effective heat transfer, within a small volume at reasonable cost.

Download Full-text

Spray-On Liquid-Metal Electrodes for Graphene Field-Effect Transistors

Micromachines ◽

10.3390/mi10010054 ◽

2019 ◽

Vol 10 (1) ◽

pp. 54 ◽

Cited By ~ 6

Author(s):

Jordan Melcher ◽

Kareem Elassy ◽

Richard Ordonez ◽

Cody Hayashi ◽

Aaron Ohta ◽

...

Keyword(s):

Liquid Metal ◽

Flexible Electronics ◽

Field Effect ◽

Field Effect Transistors ◽

Liquid Metals ◽

Chemical Vapor ◽

Channel Length ◽

High Yield ◽

Graphene Sample ◽

Viable Solution

Advancements in flexible circuit interconnects are critical for widespread adoption of flexible electronics. Non-toxic liquid-metals offer a viable solution for flexible electrodes due to deformability and low bulk resistivity. However, fabrication processes utilizing liquid-metals suffer from high complexity, low throughput, and significant production cost. Our team utilized an inexpensive spray-on stencil technique to deposit liquid-metal Galinstan electrodes in top-gated graphene field-effect transistors (GFETs). The electrode stencils were patterned using an automated vinyl cutter and positioned directly onto chemical vapor deposition (CVD) graphene transferred to polyethylene terephthalate (PET) substrates. Our spray-on method exhibited a throughput of 28 transistors in under five minutes on the same graphene sample, with a 96% yield for all devices down to a channel length of 50 μm. The fabricated transistors possess hole and electron mobilities of 663.5 cm2/(V·s) and 689.9 cm2/(V·s), respectively, and support a simple and effective method of developing high-yield flexible electronics.

Download Full-text

Liquid Metal Inks for Flexible Electronics and 3D Printing: A Review

Volume 2B: Advanced Manufacturing ◽

10.1115/imece2014-37993 ◽

2014 ◽

Cited By ~ 3

Author(s):

Lei Wang ◽

Jing Liu

Keyword(s):

3D Printing ◽

Liquid Metal ◽

Flexible Electronics ◽

Printed Electronics ◽

Liquid Metals ◽

Practical Applications ◽

Medical Sensors ◽

Push Forward ◽

Fundamental Research ◽

The Many

Flexible electronics and 3D printing are quickly reshaping the world in many aspects spanning from science, technology to industry and social society. However, there still exist many barriers to impede further progress of the areas. One of the biggest bottlenecks lies in the strong shortage of appropriate functional inks. Among the many printable materials ever tried such as conductive polymers, powdered plastic, metal particles or other adhesive materials, the liquid metal or its alloy is quickly emerging as a powerful electronic ink with diverse capabilities from which direct printing of flexible electronics and room temperature 3D printing for manufacturing metal structures are enabled. All these fabrication capabilities are attributed to the unique properties of such metal’s low melting point (generally less than 100 °C), flowable feature and high electrical conductivity etc. To better push forward the research and application of the liquid metal printed electronics and 3D manufacture, this article is dedicated to present an overview on the fundamental research advancements in processing and developing the liquid metal inks. Particularly, the flow, thermal, phase change and electrical properties of a group of typical liquid metals and their alloy inks will be systematically summarized and comparatively evaluated. Some of the practical applications of these materials in a wide variety of flexible electronics fabrication, 3D printing and medical sensors etc. will be briefly illustrated. Further, we also explained the basic categories of the liquid metal material genome towards discovering new functional alloy ink materials as initiated in the authors’ lab and interpret the important scientific and technical challenges lying behind. Perspective and future potentials of the liquid metal inks in more areas were also suggested.

Download Full-text

On Numerical Methods Used in Mathematical Modeling of Phase Change in Liquid Metals

Journal of Heat Transfer ◽

10.1115/1.3250529 ◽

1988 ◽

Vol 110 (3) ◽

pp. 562-570 ◽

Cited By ~ 56

Author(s):

D. Poirier ◽

M. Salcudean

Keyword(s):

Mathematical Modeling ◽

Heat Conduction ◽

Numerical Analysis ◽

Liquid Metal ◽

Phase Change ◽

Comparative Evaluation ◽

Single Phase ◽

Liquid Metals ◽

Effective Capacity ◽

Temperature Profiles

The work presents an analysis and comparative evaluation of different methods used for the numerical solution of heat conduction with phase change problems. Both freezing (melting) water as well as solidifying liquid metal problems are examined. Emphasis is placed on weak formulations as they tend to be simple to program and easily implemented in existing single-phase codes. A new method based on the apparent capacity technique is proposed. In this technique an “effective capacity” is computed, based on the integration of temperature profiles over the nodal volumes. This method shows significantly better performance when compared with other methods for the numerical analysis of solidifying metals.

Download Full-text