How Inkjet-printed liquid metal can help make wearable tech, soft robotics

A new study has provided a deeper insight into how Inkjet-printed liquid metal can help in producing wearable flexible tech and soft robotics.

Inkjet-printing technology can be used to mass-produce electronic circuits made of liquid-metal alloys for "soft robots" and flexible electronics.

Elastic technologies could make possible a new class of pliable robots and stretchable garments that people might wear to interact with computers or for therapeutic purposes.

However, new manufacturing techniques must be developed before soft machines become commercially feasible, said Rebecca Kramer, an assistant professor of mechanical engineering at Purdue University.

A printable ink is made by dispersing the liquid metal in a non-metallic solvent using ultrasound, which breaks up the bulk liquid metal into nanoparticles. This nanoparticle-filled ink would be compatible with inkjet printing.

After printing, the nanoparticles must be rejoined by applying light pressure, which renders the material conductive. This step is necessary because the liquid-metal nanoparticles are initially coated with oxidized gallium, which acts as a skin that prevents electrical conductivity.

The approach makes it possible to select which portions to activate depending on particular designs, suggesting that a blank film might be manufactured for a multitude of potential applications.

The process could make it possible to rapidly mass-produce large quantities of the film.

Future research will explore how the interaction between the ink and the surface being printed on might be conducive to the production of specific types of devices.

The researchers also will study and model how individual particles rupture when pressure was applied, providing information that could allow the manufacture of ultrathin traces and new types of sensors.

The study will be published in the journal Advanced Materials.