N.C. State, Chinese researchers develop elastic material impervious to gases, liquids

A team of international researchers has made an innovative breakthrough with the development of a technique that uses liquid metal to create a stretchable elastic material impervious to liquids and gases.

According to a North Carolina State University news release, the material could be used as packaging for valuable technologies, including flexible batteries that require protection from gases. The research team included scientists from North Carolina State (N.C. State), Shanghai Jiao Tong University and A123 Systems.

“This is an important step because there has long been a trade-off between elasticity and being impervious to gases,” said Michael Dickey, co-author of a paper on the work, and the Camille & Henry Dreyfus Professor of Chemical and Biomolecular Engineering at N.C. State, the release noted.

The internal surface of the material was studded with microscale glass beads, which were designed to keep the EGain liquid film from collecting. This effort resulted in an elastic bag, lined with a liquid metal, that would prevent gases or liquids from passing through the material, according to the release.

“Basically, things that were good at keeping gases out tended to be hard and stiff. And things that offered elasticity allowed gases to seep through,” Dickey said. “We’ve come up with something that offers the desired elasticity while keeping gases out.”

The researchers tested the material by assessing how much liquid material evaporated from inside and whether oxygen could escape a sealed container made from the material. No detectable loss of either oxygen or liquid was detected.

Despite the expense of the liquid materials, the research team said it believes it can make the most of the technique, possibly by making the EGain film thinner to reduce costs. 

N.C. State said researchers also are reviewing other possibilities to see if the material has other applications and can prove even more effective than first believed.

“We’re also looking for industry partners to explore potential applications for this work,” Dickey concluded. “Flexible batteries for use with soft electronics is one obvious application, but other devices that either use liquids or are sensitive to oxygen will benefit from this technology.”

According to the university, the paper, titled “Liquid metal-based soft and hermetic seals for stretchable systems,” is published in the journal Science. 

The team's efforts received support from the National Science Foundation, the National Natural Science Foundation of China, the Zhi-Yuan Endowed fund from Shanghai Jiao Tong University, and the Shanghai Jiao Tong University overseas study grants.