Self-healing and electrically conducive material marks breakthrough for softbotics

The advance from Carnegie Mellon University is said to mark a breakthrough in softbotics and the fields of robotics, electronics, and medicine. The team’s results are published in Nature Electronics, 

According to CMU, softbotics represents a new generation of soft machines and robots manufactured by multi-functional materials imbued with integrated sensing, actuation, and intelligence.

The research team introduced the material, a liquid-metal filled organogel composite with high electrical conductivity, low stiffness, high stretchability, and self-healing properties in a damage-resistant snail-inspired robot, a modular circuit to power a toy car, and a reconfigurable bioelectrode to measure muscle activity on different locations of the body.

“This is the first soft material that can maintain a high-enough electrical conductivity to support digital electronics and power-hungry devices,” lead author Carmel Majidi, Professor of Mechanical Engineering, said in a statement.  “We have demonstrated you can actually power motors with it.”

The fully untethered snail robot used the self-healing conductive material on its soft exterior, which was embedded with a battery and electric motor to control motion. During the demonstration, the team severed the conductive material and watched as its speed dropped by over 50 per cent. Because of its self-healing properties, when the material was manually reconnected, the robot restored its electrical connection and recovered 68 per cent of its original speed. 

The material can also act as a modular building block for reconfigurable circuits. In their demonstration, one piece of gel initially connected the toy car to a motor. When the team split that gel into three sections and connected one section to a roof-mounted LED, they were able to restore the car’s connection to the motor using the two remaining sections. 

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“In practice there will be cases where you want to reuse and recycle these gel-like electronics into different configurations, and our toy car demonstration shows that’s possible,” said Majidi. 

The team also demonstrated the material’s ability to be reconfigured to obtain electromyography (EMG) readings from different locations on the body. Because of its modular design, the organogel can be refitted to measure hand activity on the anterior muscles of the forearm and to the back of the leg to measure calf activity. Potential applications include tissue-electronic interfaces like EMGs and EKGs using soft, reusable materials.

“Softbotics is about seamlessly integrating robotics into everyday life, putting humans at the centre,” said Majidi. “Instead of being wired up with biomonitoring electrodes connecting patients to bio measurement hardware mounted on a cart, our gel can be used as a bioelectrode that directly interfaces with body-mounted electronics that can collect information and transmit it wirelessly.”