Jianliang Xiao, an assistant professor in CU Boulder’s Department of Mechanical Engineering and lead author said, “Many people are familiar with the movie The Terminator, in which the skin of film’s main villain is “re-healed” just seconds after being shot, beaten or run over. While the new process is not nearly as dramatic, the healing of a cut or broken e-skin, including the sensors, is done by using a mix of three commercially available compounds in ethanol.”
Indeed, an electronic skin, perceived as e-skin, is a thin, translucent material that can mimic the function and mechanical characteristics of human skin. Several types and sizes of wearable e-skins are at present being produced in labs around the world as researchers identified their utilities widely ranging from robotics and prosthetic development to better biomedical types of equipment.
Wei Zhang, an associate professor in CU Boulder’s Department of Chemistry and Biochemistry said, the new CU Boulder e-skin has sensors embedded to measure pressure, temperature, humidity and air flow.
The technology has numerous different characteristics, including a novel sort of covalently bonded dynamic network polymer, known as polyimide that has been laced with silver nanoparticles to receive better mechanical strength, chemical stability, and electrical conductivity.
Xiao stated, “What is unique here is that the chemical bonding of polyimide we use allows the e-skin to be both self-healing and fully recyclable at room temperature.”
“Given the millions of tons of electronic waste generated worldwide every year, the recyclability of our e-skin makes good economic and environmental sense.”
An additional advantage of the novel CU Boulder e-skin is that it can be easily conformed to curved surfaces like human arms and robotic hands by giving medium heat and pressure to it in absence of introduction of surplus stresses.
Zhang said, “Let’s say you wanted a robot to take care of a baby.”
“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.”
At last, to recycle the skin, the equipment is soaked into recycling solution, making the polymers degrade into oligomers (polymers with polymerization degree usually below 10) and monomers (small molecules that can be joined together into polymers) that are soluble in ethanol. The silver nanoparticles sink to the bottom of the solution.
Xiao said, “The recycled solution and nanoparticles can then be used to make new, functional e-skin.”
A paper on the subject published in the journal Science Advances.