Robot, heal thyself

A new type of soft robot can go under the knife and make a full recovery in about a day.

Researchers fashioned a robotic hand, gripper and muscle from self-healing rubbery material. To test their robots’ resilience, the engineers sliced each with a scalpel, then put them in an oven. After cranking up the heat to 80° Celsius, baking the bots for 40 minutes, then cooling them to room temperature, the researchers found that all three bots’ cuts had completely closed up. Twenty-four hours later, the machines had regained at least 98 percent of their original strength and flexibility, the researchers report online August 16 in Science Robotics.

Incisions broke bonds between two chemical ingredients that make up the material, furan and maleimide. At higher temperatures, these chemical compounds can also split up, as well as move around more easily. So as the researchers cooled the material, the compounds were able to re-bond with those on the other side of an incision.  

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’Tis but a scratch

Researchers treated their robots' injuries by heating them from 25° Celsius to 80° and cooling them down again. The process allowed chemical compounds within the material to break apart and forge new bonds that closed up the gash. 

“This material could heal, in theory, an infinite number of times,” says study coauthor Bram Vanderborght, an engineer at Vrije University Brussels.

The work helps address a major limitation of squishy, flexible robots — which are better suited than their traditional, rigid counterparts for navigating rough terrain and handling fragile objects, but are vulnerable to punctures and tears. Self-healing machines could pave the way for creating more durable, reusable soft bots.