Printing low-melting-point alloy ink to directly make a solidified circuit or functional device with a heating pen

Abstract

A new method to directly print out a solidified electronic circuit through low-melting-point metal ink is proposed. A functional pen with heating capability was fabricated. Several typical thermal properties of the alloy ink Bi 35 In 48.6 Sn 16 Zn 0.4 were measured and evaluated. Owing to the specifically selected melting point of the ink, which is slightly higher than room temperature, various electronic devices, graphics or circuits can be manufactured in a short period of time and then rapidly solidified by cooling in the surrounding air. The liquid–solid phase change mechanism of the written lines was experimentally characterized using a scanning electron microscope. In order to determine the matching substrate, wettability between the metal ink Bi 35 In 48.6 Sn 16 Zn 0.4 and several materials, including mica plate and silicone rubber, was investigated. The resistance–temperature curve of a printed resistor indicated its potential as a temperature control switch. Furthermore, the measured reflection coefficient of a printed double-diamond antenna accords well with the simulated result. With unique merits such as no pollution, no requirement for encapsulation and easy recycling, the present printing approach is an important supplement to current printed electronics and has enormous practical value in the future.

Recent Advancements in Liquid Metal Flexible Printed Electronics: Properties, Technologies, and Applications

“…Sheng et al directly painted the liquid metal ink on the surface of VHB 4905 acrylic films to manufacture a capacitor sensor ( Figure 5 A) [ 90 ]. Because of its gravity and adhesion to substrates, the liquid metal alloy can be directly installed into the refill as a kind of ink to write conductive texts or lines [ 91 , 92 ]. Zheng et al developed the liquid metal roller-ball pen (LMRP), which can write conductive lines or electronic devices on soft plates with the tip diameters ranging from 200 μm to 1000 μm ( Figure 5 B) [ 93 ].…”

Interfacial Engineering of Room Temperature Liquid Metals

“…On the other hand, taking advantage of the conductivity of liquid metals has shown promise in the area of skin electronics, [150] flexible robots, [151,152] and flexible detection sensors, [108,153,154] owing to flexible and appropriate elastic modulus of polymer substrates. To improve printing accuracy and simplicity, the preparation process of liquid metal printing ranges from manual writing, [1,155] mask deposition manufacturing, [156] to 3D printing, [154,157,158] as shown in Figure 12. Early writing and printing methods are mainly based on the wetting properties of liquid metal and polymer materials.…”

Freeze‐Printing of Liquid Metal Alloys for Manufacturing of 3D, Conductive, and Flexible Networks

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liquid metal alloys including injection of liquid metals into elastomeric channel networks, [10][11][12][13][14] freeze-casting, [15] surface patterning using lithographic techniques, [16][17][18][19] laser engraving, [20] or additive approaches including flow-based direct-writing, [21,22] droplet-by-droplet deposition, [23] heated roller-pen printing, [24,25] ink-jetting, [26] deposition at microscale in the nanoparticle ink form, followed by sintering, [27] or combination of direct-writing and transfer printing. [28] These methods have been utilized to realize various flexible electronic components including interconnects, [10,29] passive circuitry, [11] diodes and memristors, [30,31] antennas for wireless communication, [21,32,33] and wearable force and pressure sensors.

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