A few weeks ago, I highlighted scientific advances of a “self-aware” cyberslug. Not to be outdone, scientists have now developed materials that automatically make mechanical and electrical repairs to themselves when damaged. Does this mean that replicating life in all its glory is just around the corner?

The Innovation

Scientists and engineers would like to find materials with the good electrical properties of metals and the good mechanical properties of polymers. During high school, I had the opportunity to work on a rather extensive research project addressing this problem. I tested a number of specific polymers to see if any had good electrical properties and if those electrical properties could be improved without sacrificing the favorable mechanical properties. I found some polymers with reasonable electrical properties, but the electrical gains usually came at the expense of mechanical flexibility.

Where my search looked for existing polymers with good electrical properties, another group developed a completely new material: a rubber containing suspended metal droplets.1 This material exhibits good electrical and mechanical properties, plus it comes with an added benefit. When the material is cut, ripped, or punctured, the suspended metal droplets rupture and reroute the electrical connection around the damage. See the video below for a remarkable demonstration of this “healing” power.

The Implications

This may seem obvious, but virtually all life has the capacity to repair or heal itself. Cut yourself and the skin regrows over the wound. Break a bone and new material fuses the splintered pieces. So, how does this new “healing” material measure up to what we see in life? While it is a remarkable technical achievement, the new material can’t begin to compete with what life does with apparent ease.

First, the material doesn’t actually heal the punctures, rips, and cuts. It simply reroutes the electrical signals around the damage. Second, the mechanical degradation from the damage diminishes the structural integrity of the material. Third, while the material maintains electrical conductivity when damaged, the resistance of [seems like there’s a word missing here? Is this supposed to be “the resistance of the material will change” or “its resistance will change”?] will change with the amount of damage. The researchers demonstrated that the circuits continue operating, circuits with sensitivity to the resistivity of electrical components would start behaving differently when damaged. [A bit confused by the previous sentence. The third point states that the material’s resistance changes with the amount of damage, but then this sentence states that the circuits continue operating . . . ? First, is this supposed to say “continue operating as normal”? Second, doesn’t that contradict what is stated in the previous sentence? SO CONFUSED.]

This new material shows that humanity continues to make amazing strides in our quest to mimic nature. The failure to live up to life’s standards doesn’t negate the remarkable accomplishment of the researchers. The fact that life repeatedly exhibits better designs and outpaces our technological advancements simply demonstrates the incredible mind responsible for all life on Earth.

Endnotes

1. Eric J. Markvicka et al., “An Autonomously Electrically Self-Healing Liquid Metal–Elastomer Composite for Robust Soft-Matter Robotics and Electronics,” Nature Materials 2018 (May 21, 2018): doi:10.1038/s41563-018-0084-7.