S u m m a r y :
A new self-healing, malleable, and recyclable electronic skin has been engineered in a recent study published in the journal Science Advances.
New E-Skin With Great Potential
We can add a new type of ‘prosthetic’ in the list: a self-healing, malleable, and 100% recyclable electronic skin (e-skin) that promises to have applications in robotics, and the development of prosthetics and biomedical devices. The minds from which the e-skin budded off are researchers from the University of Colorado Boulder.
Silver Nanoparticles & Sensors
E-skins have built a name for themselves in the last few years: they currently exist in different forms and sizes. They are generally thin and translucent with the capacity to reproduce the functional and mechanical characteristics of human skin. They are deemed important in various fields, from medicine to engineering.
The CU Boulder e-skin stands out because of its material: a polymer known as polyimine that is held together by covalent bonds. The polyimine incorporates silver nanoparticles that are meant to boost mechanical strength, chemical stability, and electrical conductivity. Furthermore, it has sensors to take measurements for pressure, temperature, humidity, and air flow, explains lead researcher Jianliang Xiao.
The e-skin can also fit around curved surfaces such as those characterising human arms and robot hands; the curving is brought about by exposing it to moderate heat and pressure.
The authors have kept in mind the need to protect the environment when they designed the e-skin, which is why they made the device recyclable.
“What is unique here is that the chemical bonding of polyimine we use allows the e-skin to be both self-healing and fully recyclable at room temperature,” said Xiao. “Given the millions of tons of electronic waste generated worldwide every year, the recyclability of our e-skin makes good economic and environmental sense.”
The recycling is done by soaking the device into recycling solution which degrades the polymers into ethanol-soluble oligomers, the form existing below polymerisation degree 10, and monomers, the building blocks of polymers. At the end of the process, the silver nanoparticles settle at the bottom of the solution, and together with the recycled solution, they are used to create new e-skin, explains Xiao.
How does the Self-Healing Happen?
Study author Wei Zhang explains that cuts are easily ‘healed’ through a combination of 3 compounds with ethanol. He likens the process with the movie The Terminator whose villains had skin that would be healed within seconds; of course, the real thing is not as extraordinary as the sci-fi version, but yes, it can totally be used on robots! The idea is to mimic the human touch.
“Let’s say you wanted a robot to take care of a baby,” said Zhang. “In that case you would integrate e-skin on the robot fingers that can feel the pressure of the baby. The idea is to try and mimic biological skin with e-skin that has desired functions.”