Professor Ilkwon Oh and doctoral candidate Jae Hwan Kim from the Division of Ocean System Engineering under the School of Mechanical Aerospace and Systems Engineering, working in coordination with Doctor Hyuneui Lim, the head of the Nano-Biomimetic Research Lab at the Korea Institute of Machinery & Materials, succeeded in developing an artificial muscle that is durable and floatable, and has an effective operating period ten times longer than current artificial muscles.

 Existing ionic-polymer artificial muscles resemble human muscles and have excellent output per volume, making them possible candidates for the replacement of mechanical motors and hydraulic systems. However, as their internal electrolytes seep through the cracks on the surface of the platinum electrode, their durability decreases, making them difficult to commercialize. Professor Oh’s research team solved this problem by changing the electrode from platinum to graphene, which is pure carbon in the form of a very thin, one-atom sheet. Graphene, compared to platinum, has similar electrical conductivity, but the distance between particles is smaller. In fact, the size of the internal electrolyte ion is larger than the distance between particles of a five-micrometer-thick stacked graphene oxide electrode. Also, by treating the electrolyte-contacting surface area with lasers to increase the surface area, adhesiveness is enhanced, resulting in higher durability while the muscle is in motion. One more interesting characteristic of graphene is that it tends to push away water, making it ideal for the newly developed artificial muscle to float in water.

 The platinum artificial muscles operate at 4.5 volts and 1 hertz for 6 hours showed more than a 50 percent decrease in movement after 30 minutes, while the research team’s graphene artificial muscle in the same conditions continued to maintain movement similar to the start of the experiment even after 30 minutes, which is demonstrative of its stability. Professor Oh commented, “By simply changing the electrode, we solved the fundamental problem regarding the actuator in artificial muscles. We hope that within a few years, we will be able to develop applied electronic devices using this technology.” This research was published in the American Chemical Society’s journal ACS Nano.