South Korean scientists from Seoul National University and Gachon University have presented a “liquid” chameleon robot – Particle-armored liquid roBot (PB), a drop of water wrapped in a super-dense shell of Teflon particles. Science Advances reported that PB can shrink, stretch, and slip through holes smaller than its diameter. The key to success is “armor” <150 µm thick, which can withstand a drop of 30 cm and a pressure of hundreds of kPa. On May 23, Mashable named PB the smallest robot hit of the year and showed how the robot drop swallows a glass ball and then “spits” it out at the right point.
Demonstration of PB’s ability to pass through grid obstacles. Source: Science Advanced
The PB is propelled by ultrasonic waves at speeds of up to 15 mm/s, can split into several “scout droplets”, merge back together, and capture foreign particles, working like a microscopic dust collector. Due to the absence of toxic metals and high impact strength, dozens of these droplets can be injected en masse into narrow fuel channels, heat exchangers, or spacecraft panel joints for photo-diagnostics, deposit removal, and leakage testing without disassembling the modules.
The researchers are already planning to integrate magnetic nanoparticles and electrostatic control, which will allow the PB to be guided in microgravity, where ultrasound does not propagate in a vacuum. Such a “liquid service crew” would be able to deliver sealants or catalysts precisely into microcracks, perform chemical analysis, and even merge into larger volumes for more complex repairs. This opens the way to servicing orbital stations and satellites without costly spacewalks by extending the life of the vehicles through robotic droplets that work invisibly inside structures.
And in the electromagnetic catapult projects we discussed earlier, PB would be able to rapidly diagnose and eliminate micro-cracks in superconducting rails or vacuum chambers, extending the system’s lifespan and reducing the risk of sudden failures under high currents.
