Researchers Wrap Nanotubes Around Rubber Core Sparking a Creation That May Lead to Artificial Muscles, Sensors
An international research team based at The University of Texas at Dallas has made electrically conducting fibers that can be reversibly stretched to over 14 times their initial length and whose electrical conductivity increases 200-fold when stretched.
The research team is using the new fibers to make artificial muscles, as well as capacitors whose energy storage capacity increases about tenfold when the fibers are stretched. Fibers and cables derived from the invention might one day be used as interconnects for super-elastic electronic circuits; robots and exoskeletons having great reach; morphing aircraft; giant-range strain sensors; failure-free pacemaker leads; and super-stretchy charger cords for electronic devices.
In a study published in the July 24 issue of the journalScience, the scientists describe how they constructed the fibers by wrapping lighter-than-air, electrically conductive sheets of tiny carbon nanotubes to form a jelly-roll-like sheath around a long rubber core.
The new fibers differ from conventional materials in several ways. For example, when conventional fibers are stretched, the resulting increase in length and decrease in cross-sectional area restricts the flow of electrons through the material. But even a “giant” stretch of the new conducting sheath-core fibers causes little change in their electrical resistance, said Dr. Ray Baughman, senior author of the paper and director of the Alan G. MacDiarmid NanoTech Institute at UT Dallas.
One key to the performance of the new conducting elastic fibers is the introduction of buckling into the carbon nanotube sheets. Because the rubber core is stretched along its length as the sheets are being wrapped around it, when the wrapped rubber relaxes, the carbon nanofibers form a complex buckled structure, which allows for repeated stretching of the fiber.
“Think of the buckling that occurs when an accordion is compressed, which makes the inelastic material of the accordion stretchable,” said Baughman, the Robert A. Welch Distinguished Chair in Chemistry at UT Dallas.
“We make the inelastic carbon nanotube sheaths of our sheath-core fibers super stretchable by modulating large buckles with small buckles, so that the elongation of both buckle types can contribute to elasticity. These amazing fibers maintain the same electrical resistance, even when stretched by giant amounts, because electrons can travel over such a hierarchically buckled sheath as easily as they can traverse a straight sheath.”
Dr. Zunfeng Liu, lead author of the study and a research associate in the NanoTech Institute, said the structure of the sheath-core fibers “has further interesting and important complexity.” Buckles form not only along the fiber’s length, but also around its circumference.
“Shrinking the fiber’s circumference during fiber stretch causes this second type of reversible hierarchical buckling around its circumference, even as the buckling in the fiber direction temporarily disappears,” Liu said. “This novel combination of buckling in two dimensions avoids misalignment of nanotube and rubber core directions, enabling the electrical resistance of the sheath-core fiber to be insensitive to stretch.”
By adding a thin overcoat of rubber to the sheath-core fibers and then another carbon nanotube sheath, the researchers made strain sensors and artificial muscles in which the buckled nanotube sheaths serve as electrodes and the thin rubber layer is a dielectric, resulting in a fiber capacitor. These fiber capacitors exhibited a capacitance change of 860 percent when the fiber was stretched 950 percent.
“No presently available material-based strain sensor can operate over nearly as large a strain range,” Liu said.
The Latest on: Conducting elastic fibers
[google_news title=”” keyword=”conducting elastic fibers” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Conducting elastic fibers
- New computer virus causes havocon February 28, 2024 at 3:59 pm
A powerful new computer virus was today causing havoc with e-mail systems across the world. Experts described the virus, called Goner, as one of the fastest-spreading they had yet seen and warned ...
- What is Alaskapox? Symptoms to know after death brings attention to viruson February 14, 2024 at 1:27 pm
News that an elderly man in Alaska has died from Alaskapox — the first known fatality, according to state health officials — has brought newfound attention to the recently discovered virus.
- A Man Has Died From Alaskapox. Here’s What We Know About the Viruson February 13, 2024 at 12:54 pm
Alaska’s health department reports that the first person in the state has died from a recently discovered virus called Alaskapox. The elderly man—who was immunocompromised due to cancer ...
- What is Alaskapox? First fatality reported from animal-borne virus, likely contracted from stray caton February 12, 2024 at 6:50 pm
The first fatality from Alaskapox, a type of orthopoxvirus, has been reported on the Kenai Peninsula of Alaska. State officials released a bulletin on Feb. 9 detailing that an elderly man ...
- Man Dies in First Known Fatal Case of Alaskapoxon February 12, 2024 at 4:00 pm
An Alaska man died last month of Alaskapox, a rare virus that occurs mostly in small mammals and can cause skin lesions, according to state health officials. Alaskapox was first identified in 2015 ...
- What Is Alaskapox? Symptoms and Origins of Viruson February 12, 2024 at 8:51 am
With officials announcing the death of the first person due to the recently discovered Alaskapox, experts have raised concerns that the virus may have spread farther across the state amongst its ...
- Cambodia reports new bird flu case after brother of 9-year-old who died of the virus tests positiveon February 12, 2024 at 8:42 am
The brother of a 9-year-old boy who died from bird flu in Kratie province, Cambodia, has tested positive for the virus. The boy's death was the first reported case of bird flu in Cambodia this year.
- What to know about rare virus Alaskapox after 1st fatal caseon February 12, 2024 at 5:13 am
The virus was first identified in Fairbanks in 2015, the Alaska DOH says. An Alaska resident has died from complications of a relatively new and rare virus known as Alaskapox, according to a ...
- Your Mac Is Not Virus Proof. It Never Has Been.on February 11, 2024 at 3:59 pm
He stood next to a visibly sick man, claiming to be a PC. “I have that virus that’s going around,” said the PC man. “You better stay back, this one’s a doozy.” “That’s okay ...
- Virus ancestry could help predict next pandemicon February 4, 2024 at 4:00 pm
Virus family history could help scientists identify which strains have the potential to become the so-called Disease X that causes the next global pandemic. A new study published in Molecular ...
via Bing News