3D printing smart clothes with a new, flexible, liquid metal microgel ink
In the future, smart clothing might monitor our posture, communicate with smartphones and manage our body temperature.

[Apr 14, 2022: Pengcheng Wu, American Chemical Society]
In the future, smart clothing might monitor our posture, communicate with smartphones and manage our body temperature. (CREDIT: Butler Technologies)
In the future, smart clothing might monitor our posture, communicate with smartphones and manage our body temperature. But first, scientists need to find a way to cost-effectively print intricate, flexible and durable circuits onto a variety of fabrics.
Now, researchers reporting in ACS Applied Materials & Interfaces have developed a conductive 3D printing ink made of liquid metal droplets coated with alginate, a polymer derived from algae.
Conventional electronics are rigid and unable to withstand the twisting and stretching motions that clothing undergoes during typical daily activities. Because of their fluid nature and excellent conductivity, gallium-based liquid metals (LMs) are promising materials for flexible electronics. However, LMs don't stick well to fabrics, and their large surface tension causes them to ball up during 3D printing, rather than form continuous circuits. Yong He and colleagues wanted to develop a new type of conductive ink that could be 3D printed directly onto clothing in complex patterns.
Graphical abstract. (CREDIT: ACS Applied Materials & Interfaces (2022). DOI: 10.1021/acsami.1c22975)
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To make their ink, the researchers mixed LM and alginate. Stirring the solution and removing the excess liquid resulted in LM microdroplets coated with an alginate microgel shell. The ink was very thick until it was squeezed through a nozzle for 3D printing, which broke hydrogen bonds in the microgel and made it more fluid. Once the ink reached the fabric surface, the hydrogen bonds reformed, causing the printed pattern to maintain its shape.
The team 3D printed the new ink onto a variety of surfaces, including paper, polyester fabrics, nonwoven fabrics and acrylic-based tape. Although the printed patterns were not initially conductive, the researchers activated them by stretching, pressing or freezing, which ruptured the dried alginate networks to connect the LM microdroplets.
After activation, the printed circuits had excellent electrical conductivity and strain sensing properties. In addition, applying a small voltage to the ends of the circuit caused it to heat up, even in very cold temperatures.
(CREDIT: American Chemical Society)
To demonstrate the ink's capabilities, the team 3D printed a series of electronics onto commercial clothing. On a T-shirt, they printed a near-field communication tag that directed a smartphone placed nearby to open a web site. Other sensors printed on clothing monitored the motion of an elbow or knee joint. And a circuit powered by a small battery heated up the printed pattern to above 120 F in less than a minute.
The LM-alginate ink can be recycled by soaking the fabric in a weak sodium hydroxide solution, recovering fresh liquid metal for new applications.
Note: Materials provided above by American Chemical Society. Content may be edited for style and length.
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Tags: #New_Innovations, #3D_Printing, #Ink, #Health_News, #Flexibility, #Smart_Clothes, #Science, #Technology, #The_Brighter_Side_of_News

Joseph Shavit
Science News Writer, Editor-At-Large and Publisher
Joseph Shavit, based in Los Angeles, is a seasoned science journalist, editor and co-founder of The Brighter Side of News, where he transforms complex discoveries into clear, engaging stories for general readers. With experience at major media groups like Times Mirror and Tribune, he writes with both authority and curiosity. His work spans astronomy, physics, quantum mechanics, climate change, artificial intelligence, health, and medicine. Known for linking breakthroughs to real-world markets, he highlights how research transitions into products and industries that shape daily life.