HomeNewsArticle Display

Air Force scientists discover unique stretchable conductor

The Air Force Research Laboratory developed Polymerized Liquid Metal Network rupturing to transform into a highly stretchable design that autonomously increases conductivity with strain. (Courtesy Image/Second Bay Studios.)

An illustration shows Polymerized Liquid Metal Network, developed by the Air Force Research Laboratory, rupturing to transform into a highly stretchable design that autonomously increases conductivity with strain. (U.S. Air Force courtesy graphic by Second Bay Studios)

WRIGHT-PATTERSON AIR FORCE BASE, Ohio (AFNS) --

The Air Force Research Laboratory has developed liquid metal systems which autonomously change structure so that they become better conductors in response to strain.

Conductive materials change their properties as they are strained or stretched. Typically, electrical conductivity decreases and resistance increases with stretching.

The material recently developed by AFRL scientists, called Polymerized Liquid Metal Networks, does just the opposite. These liquid-metal networks can be strained up to 700%, autonomously respond to that strain to keep the resistance between those two states virtually the same and still return to their original state. It is all due to the self-organized nanostructure within the material that performs these responses automatically.

“This response to stretching is the exact opposite of what you would expect,” Dr. Christopher Tabor, AFRL lead research scientist on the project said. “Typically a material will increase in resistance as it is stretched simply because the current has to pass through more material. Experimenting with these liquid-metal systems and seeing the opposite response was completely unexpected and frankly unbelievable until we understood what was going on.”

Wires maintaining their properties under these different kinds of mechanical conditions have many applications, such as next-generation wearable electronics. For instance, the material could be integrated into a long-sleeve garment and used for transferring power through the shirt and across the body in a way that bending an elbow or rotating a shoulder won’t change the power transferred.

AFRL researchers also evaluated the material’s heating properties in a form factor resembling a heated glove. They measured thermal response with sustained finger movement and retained a nearly constant temperature with a constant applied voltage, unlike current state-of-the-art stretchable heaters that lose substantial thermal power generation when strained due to the resistance changes. These properties and the material fabrication details are directly compared in the current issue of Advanced Materials at https://doi.org/10.1002/adma.201903864.

This project started within the last year and was developed in AFRL with fundamental research dollars from the Air Force Office of Scientific Research. It is currently being explored for further development in partnership with both private companies and universities. Working with companies on cooperative research is beneficial because they take early systems that function well in the lab and optimize them for potential scale up. In this case, they will enable integration of these materials into textiles that can serve to monitor and augment human performance.

The researchers start with individual particles of liquid metal enclosed in a shell, which resembles a water balloon. Each particle is then chemically tethered to the next one through a polymerization process, akin to adding links into a chain; in that way, all of the particles are connected to each other.

As the connected liquid metal particles are strained, the particles tear open and liquid metal spills out. Connections form to give the system both conductivity and inherent stretchability. During each stretching cycle after the first, the conductivity increases and returns back to normal. To top it off, there is no detection of fatigue after 10,000 cycles.

“The discovery of Polymerized Liquid Metal Networks is ideal for stretchable power delivery, sensing and circuitry,” said Capt. Carl Thrasher, AFRL Materials and Manufacturing Directorate research chemist and lead author on the journal article. “Human interfacing systems will be able to operate continuously, weigh less and deliver more power with this technology.”

“We think this is really exciting for a multitude of applications,” he added. “This is something that isn’t available on the market today so we are really excited to introduce this to the world and spread the word.”

Engage

Twitter
“When asked whether we still require all three of these legs of the triad, I answer, ‘we do’...we must acknowledge… https://t.co/atezdKA5tT
Twitter
RT @USAFReserve: Battling #COVID; a cyber Airman’s story - https://t.co/HsJv6J7r2A #ReserveReady #ReserveResilient #ReadyAF https://t.co/y7…
Twitter
RT @USAFReserve: #ReserveCitizenAirman makes life-saving decision - https://t.co/ZPviQZRrEX (Story by the @307BombWing) #ReserveReady #Rese
Twitter
The Impact of Sharing Stories of Recovery and Resiliency Lt Col Katharine McGregor did not know much about the… https://t.co/17VibuxnTc
Twitter
Many search for years to find their true passion in life. For Staff Sgt. Camrin Northrop, a firefighter for both th… https://t.co/QcNrBXPCV0
Twitter
From their homes to yours, check out the @AirNatlGuard Band of the South! #ReadyAF #AimHigh https://t.co/yb7GhZZ5A3
Twitter
Reintegration will be a deliberate & phased approach to protect Airmen & Space Professionals. Learn to maintain rea… https://t.co/egQSAV5uRB
Twitter
The MQ-1B Predator is an armed, multi-mission, medium-altitude, long-endurance remotely piloted aircraft used for i… https://t.co/livZYQyXnH
Twitter
Dr. Quinton Sasnett, a faculty member at Air University, talks about the university's civilian associates degree pr… https://t.co/0BgoCiGCUy
Twitter
Improving mental health through expressive writing. @KadenaAirBase https://t.co/zVoYTQQl5z
Twitter
Medical pros at Kadena Air Base, 3-D printed naso-pharyngeal swabs to test potential #COVID19 patients. The dental… https://t.co/h8q1HgLjRZ
Twitter
The MC-12W is a medium-to low-altitude, twin-engine turboprop aircraft. Its primary mission is providing intelligen… https://t.co/st7WRJLDHB
Twitter
Know what resources, treatments & therapies are available for invisible wounds. https://t.co/H2A7fYb8s3
Twitter
“The Total Force team at Eielson plays a pivotal role that extends throughout Alaska and projects into the Arctic.”… https://t.co/7nSYEtYWHj
Twitter
RT @AETCommand: 🙌🎉 Congrats to the @usairforce's newest pilots as Specialized Undergraduate Pilot Training Class 20-18 graduates today at @…
Twitter
.@JointBasePHH Airmen participate in a ramp drop from a C-17 Globemaster III. The 25th Air Support Ops Squadron is… https://t.co/AZVT6Qzmgv
Twitter
RT @SecAFOfficial: It is a pleasure to be in #Alaska to see #Airmen and #SpaceProfessionals in action! Whether it’s F-35s & F-22s protectin…
Twitter
RT @EielsonAirForce: When @SecAFOfficial comes to visit, we show off the 'cool stuff' https://t.co/sGCSnVOOXg
Facebook
The newest Air Force Podcast recently dropped. Listen to a small snippet of CMSAF Kaleth O. Wright talk with Staff Sgt. New about resiliency. Listen to the entire podcast on Youtube: https://go.usa.gov/xpnAD or Subscribe to The Air Force Podcast on iTunes: https://podcasts.apple.com/podcast/the-air-force-podcast/id1264107694?mt=2
Facebook
Our mantra, "Always ready!" It's the spirit we fly by! #B2Tuesday
Facebook
Need some motivation to get your week started off right? Listen as CMSAF Kaleth O. Wright weighs in...
Facebook
The U.S. Air Force Academy gives its cadets some unique opportunities. Ride along one of this opportunities.
Facebook
A United States Air Force KC-135 Stratotanker refuels an F-22 Raptor over northern Iraq, Nov. 6, 2019. U.S. Central Command operations deter adversaries and demonstrate support for allies and partners in the region. (Video by Staff Sgt. Daniel Snider)
Facebook
Although the Silver Star is the third-highest military medal, it's not given often. Today, TSgt Cody Smith was the 49th Special Tactics Airman to receive this medal since Sept. 11th, 2001. Read more of TSgt Smith's amazing story: https://www.airforcespecialtactics.af.mil/News/Article-Display/Article/2024815/special-tactics-airman-battled-through-injuries-awarded-silver-star/fbclid/IwAR2LZWwx1VHdTnQe39rIEBOuJS_0JvMQBBGt7I-E6zsxxn-Lx9387yu43Bc/ Cannon Air Force Base Air Force Special Operations Command United States Special Operations Command (USSOCOM) U.S. Department of Defense (DoD)
Facebook
Tune in as our Air Force musicians along with other military musicians are awarded the National Medal of Arts.
Facebook
Like Us
Twitter
1,252,626
Follow Us