A kirigami design where the cuts’ length-to-width ratio was six was way more responsive to magnets, and that, in turn, enhanced an effect known as magnetically induced stiffening. With no magnets around, the kirigami disk was way more compliant than one without cuts. But when a magnetic field was applied, it became more than 1.8 times stiffer.
Overall, the kirigami dome could lift an object weighing 43.1 grams (28 times its own weight) to a height of 2.5 millimeters and hold it there. To test what this technology could do, Yin’s team built a 5×5 array of domes actuated by movable permanent magnetic pillars placed underneath that could move left or right, or spin. The array could precisely move droplets, potato chips, a leaf, and even a small wooden plank. It could also rotate a petri dish.
Next-gen haptics
The team thinks one possible application for this technology is precise transport and mixing of very tiny amounts of fluids in research laboratories. But there is another, arguably more exciting option. Chi’s shape-shifting surface is very fast; it reacts to changes in the magnetic field in under 2 milliseconds, which is a response time rivaling gaming monitors.
This, according to the team, makes it possible to use in haptic feedback controllers. Super-fast, magnetically actuated shape-shifting surfaces could emulate the sense of touch, texture, and feel of the objects you interact with wearing your VR goggles. “I’m new to haptics, but considering you can change the stiffness of our surfaces by modulating the magnetic field, this should enable us to recreate different haptic perceptions,” Yin says.
Before that becomes a reality, there is one more limitation the team must overcome.
If you compared Yin’s shape-shifting surface to a display where each dome stands for a single pixel, the resolution of this display would be very low. “So, there is the question how small can you make those domes,” Yin says. He suggested that, with advanced manufacturing techniques, it is possible to miniaturize the domes down to around 10 microns in diameter. “The challenge is how we do the actuation at such scales—that is something we focus on today. We try to pave the way but there is much more to do,” Chi adds.
Science Advances, 2024. DOI: https://doi.org/10.1126/sciadv.adr8421
