Invisible robots overshadowed by metallic hydrogen

Metallic debate: Silvera, Ceperley and McMahon discuss metallic hydrogen. (Courtesy: Sarah Tesh)

By Sarah Tesh in New Orleans, Louisiana, US

After much coffee and a lot of crispy bacon, the second day of the APS March Meeting began. The hot topic of the day – metallic hydrogen. Even though we arrived 15 minutes early to Isaac Silvera‘s talk, the crowd was overflowing from the room, but despite all the pushing and shoving (my foot has not recovered from being stood on), we did manage to get seats. Silvera began by saying that he had been working on the problem for “probably longer than [most of us] were born” before taking us through the nearly 45 years of research on the subject. He also gave a press conference that included talks by theoretical physicists David Ceperley from the University of Illinois and Jeffrey McMahon from Washington State University. My colleague Tushna Commissariat caught up with Silvera later on, so be on the lookout for a more detailed update from her.

In a biomedical session, we heard how Xuanhe Zhao of Massachusetts Institute of Technology recently developed “invisible soft robots” made of hydrogels. These nifty devices are both optically and acoustically invisible. Zhao and his team use the fact that hydrogels expand when water is pumped into them. By having different densities of hydrogel within one block, it can bend when water is pumped in. Zhao showed us a film of their “claw robot” made of hydrogel and controlled with hydraulic power. The strength of the hydrogel, its controlled flexibility and the layer of waterproof material on the outside, means the claw can pick up objects underwater. Zhao hopes such water-based soft robots and materials could have biomedical applications because the human body contains sufficient amounts of water.