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
RT @DefenseOne: JOIN US TODAY @ 2 P.M. ET when our “State of Defense” series continues with a live interview featuring U.S. Air Force Chief…
Twitter
RT @DeptofDefense: Teaching service members how to effectively shoot weapons. That’s the job of Combat Arms Training and Management. Watch…
Twitter
RT @cmsaf_official: Team - 25 years ago today, we lost 24 U.S. & Canadian Airmen in the Yukla 27 crash. It was a surveillance training so…
Twitter
Taking care of Airmen and their families! https://t.co/AVeidzDPcV
Twitter
Wherever Airmen go, the Federal Voting Assistance Program ensures their voice is heard. @FVAP works to ensure servi… https://t.co/tkJts1yo3Z
Twitter
RT @AirNatlGuard: For #HispanicHeritageMonth, we're celebrating the stories of Hispanic & Latino Airmen! @188thWG SSgt. Emmanuel Gutierrez…
Twitter
#TotalForce Airmen participate in night operations during a base-wide, total force exercise @HAFB. Airmen & pilots… https://t.co/kJYNKwHY7n
Twitter
RT @USAFReserve: California fires/smoke no match for UTA Airmen - https://t.co/pJysQ6snRh (Story by the @940Wing) #ReserveReady #ReserveRes
Twitter
Whistleblowers are NOT insider threats. Learn the difference and how you can appropriately report questionable gove… https://t.co/AaTvBfHcTv
Twitter
SrA Denise Arabie, 319th Operations Support Squadron radar approach controller @319thRW, describes the importance o… https://t.co/zkwMx6Qw3i
Twitter
RT @173rdFW: "I may have lost everything, but thanks to the support we’ve found here, I’m going to be back on my feet inside of a few weeks…
Twitter
.@GenCQBrownJr & @cmsaf_official sat down and discussed how the Air Force will continue exempting Airmen from PT t… https://t.co/bWVig9fSOW
Twitter
SrA Mark Gonzalez describes how his job enables the B-2 Spirit Stealth Bomber to support the Bomber Task Force depl… https://t.co/sceKCtM3Pz
Twitter
RT @AETCommand: Our Airmen come from all walks of life — and we are stronger for it. Staff Sgt. Kalinin, 56th Force Support Squadron ALS…
Twitter
“It's critical to have that diversity in the Air Force that we have today because it is truly through that diversit… https://t.co/RIDQDjdlCr
Twitter
F-16 Fighting Falcons assigned to the 18th Aggressor Squadron @EielsonAirForce takeoff in support of exercise Valia… https://t.co/cf0raGgEUD
Twitter
RT @USAF_ACC: "This test, and others like it, can shape the future of the MQ-9, as we continue to increase its relevance in great power com…
Twitter
"We cannot rest on our laurels. It is all about the people, folks, and they will guarantee our readiness, and are f… https://t.co/BsNDUSw0wE
Twitter
RT @USAFCENT: USAFCENT Airmen and coalition partners are executing missions of national, regional and global importance and Exercise Desert…
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
1,281,142
Follow Us