In this video, we demonstrate the process that we use for braiding carbon nanotube fibers to make EMI shielding braids or braided CNT yarns. These braids are lightweight and highly flexible. They are also more conductive than stainless steel fiber braids and much stronger than copper wire.
This video demonstrates the array of carbon nanotube tapes that DexMat currently produces. Strong, conductive, and flexible tapes or films up to 5 cm wide are currently available and even wider tape formats are currently under development.
These tapes have tremendous potential in applications ranging from EMI shielding in cables/electronics, to thermal interface materials, to heating elements or conductive materials in clothing or e-textiles.
This video shows how carbon nanotube (CNT) fibers can be assembled into yarns or ropes by plying the fibers together with a planetary ropemaking machine. These yarns are lightweight and highly flexible. They are also more conductive than stainless steel thread and much stronger than copper wire.
Last month we had the opportunity to show off our carbon nanotube yarns and films at the IdTechEx conference in Santa Clara, CA. In this video, Dmitri describes the various materials and applications that we spoke about at our booth. It was a great show, and we are excited to return to other IdTechEx events in the future!
Abstract: The above video demonstrates how carbon nanotube fibers are integrated into a spacesuit to help spacesuits mitigate dust contamination for future lunar and Mars missions.The spacesuit fabrication and testing was performed by researchers from the University of North Dakota, Boeing, and the NASA Glenn Research Center. CNT fibers were produced by DexMat.
Spacesuit dust mitigation has been a topic of high relevance and a critical path for future planetary exploration missions including Moon, Mars and Asteroids. A previous study demonstrated utilizing Carbon Nanotube (CNT) yarns as electrodes embedded into coupons made of spacesuit outer-layer material. When a multiphase Alternating Current (AC) voltage signal was applied to this material, the spacesuit fabric repelled greater than 80% lunar dust simulant with particle sizes between 10-75m in ambient conditions. As a continuation to this study, the feasibility of scaling the CNT embedded dust removal system on larger portions of spacesuit is investigated. A scaled prototype, representative of the knee joint section of a planetary spacesuit utilizing specifics of the NDX-2 lunar spacesuit developed by University of North Dakota was constructed. The outer-layer of this prototype is embedded with the CNT dust removal system and tested under various conditions. Fabrication of this system and results from the experiments using lunar dust simulant are detailed in this paper.
Researchers in South Korea made a tiny loudspeaker, and then used it to play a violin concerto
A variety of nanomaterials have been used over the years in loudspeakers and microphones. Nanoparticles have replaced permanent magnets in loudspeakers and a thin film of carbon nanotubes has done pretty much the same. And, of course, someone tried to use graphene to reproduce sound for microphones.
Now researchers at Ulsan National Institute of Science and Technology (UNIST) in South Korea have made a nanomembrane out of silver nanowires to serve as flexible loudspeakers or microphones. The researchers even went so far as to demonstrate their nanomembrane by making it into a loudspeaker that could be attached to skin and used it to play the final movement of a violin concerto—namely, La Campanella by Niccolo Paganini.
In research described in the journal Science Advances, the Korean researchers embedded a silver nanowire network within a polymer-based nanomembrane. The decision to use silver nanowires rather than the other types of nanomaterials that have been used in the past was based on the comparative ease of hybridizing the nanowires into the polymer.
In addition, the researchers opted for nanowires because the other materials like graphene and carbon nanotubes are not as mechanically strong at nanometer-scale thickness when in freestanding form, according to Hyunhyub Ko, an associate professor at UNIST and coauthor of the research. It is this thickness that is the critical element of the material.
“The biggest breakthrough of our research is the development of ultrathin, transparent, and conductive hybrid nanomembranes with nanoscale thickness, less than 100 nanometers,” said Ko. “These outstanding optical, electrical, and mechanical properties of nanomembranes enable the demonstration of skin-attachable and imperceptible loudspeaker and microphone.”
The nanomembrane loudspeaker operates by emitting thermoacoustic sound through the oscillation of the surrounding air brought on by temperature differences. The periodic Joule heating that occurs when an electric current passes through a conductor and produces heat leads to these temperature oscillations.
For the operation of the microphone, the hybrid nanomembrane is sandwiched between elastic films with tiny patterns. In this way, the nanomembrane can precisely detect the sound and the vibration of the vocal cords based on a triboelectric voltage that results from the contact with the elastic films. In these loudspeakers and microphones, the silver nanowires enable both the electrical conductivity and give the nanomembranes their freestanding strength.
While the researchers demonstrated the technology by applying a thin film of the nanomembrane on skin, this may not turn out to be a practical application of the technology, according to the researchers. This is because the performance of the thermoacoustic loudspeaker is proportional to the speaker size and temperature change of the speaker.
If it were directly attached to the skin, the input power level per unit area would increase too much for the generation of a large sound.
Ko added: “For the commercial applications, the mechanical durability of nanomebranes and the performance of loudspeaker and microphone should be improved further.”
Physicists from the University of Cincinnati will soon be able to charge smartphones using clothes made from carbon nanotubes. With the assistance of their colleagues from the BBC, Wright-Patterson, the experts intend to create a special material, which because of the peculiarities of carbon nanotubes would be exceptionally heat-resistant conducting electricity, and will also differ for their durability. Professor mark Schultz, is also involved in the study declared that the task of scientists is to use the resistance and conductivity for energy storage, which can charge a variety of gadgets.
Schulz said that at the moment the science is on the verge of a “carbon revolution,” as this material may soon completely replace metals because of its strength, low weight and various additional properties. Yarns made from nanotubes can store energy, replacing bulky batteries, which soon altogether sink into oblivion.
Full Article: https://sivtelegram.media/physics-charge-smartphones-clothes-made-from-carbon-nanotubes/30672/
New Knitting Technique Produces Electronic Smart Fabrics at Industrial Scales
Meet the bike shorts of the future.
Australian scientists have developed a knitting technique capable of producing electrically-conductive Spandex-carbon nanotube hybrid textiles at industrial scales. As described earlier this month in a paper published in ACS Nano, http://pubs.acs.org/doi/abs/10.1021/acsnano.6b04125 the stretchable fabrics “exhibit excellent performance” as sensors and artificial muscles. Potential applications include adjustable smart clothing, robotics, and medical devices.
At the core of the material is regular old Spandex, which is basically artificial super-rubber spun into fibers. In the process outlined in the paper, SPX filaments are coated with aerogel sheets of carbon nanotubes. Carbon nanotubes have the neat property of tunable electrical conductivity, and by tweaking the fabrication process, it’s possible to create materials with electrical and mechanical properties that change as the fabric changes shape. Meet the bike shorts of the future.
“The coating method operates at room temperature, requires no solvents, and does not compromise textile production speeds,” the Australian team reports. As such, the hybrid yarns are also pretty cheap to produce—a key requirement.
What makes the stuff really interesting is how it converts electricity into mechanical work. With an applied voltage, it’s possible to get the textile to contract by as much as 33 percent as it heats up. The material then relaxes as the voltage is removed and it cools down. This mechanical power output maxes out at around 1.28 kW/kg, which, the paper notes, is well beyond what’s offered by mammalian skeletal muscle. To demonstrate, the researchers used their new material to implement a knee brace, as below:
Another possible biomedical application is as a “lymph sleeve,” a compression sleeve used to treat lymphedema, a common side effect of cancer treatments.
“The lymph sleeve, for example, will be developed using lightweight actuating fabric that will detect swelling and then respond by ‘squeezing’ the arm to enhance lymph flow,” Javad Foroughi, the lead author of the new paper, told Physics World. “We are also investigating the possibility of employing it in artificial-heart muscles for positive support of the right ventricle.”
Original story by Michael Byrne / Motherboard Vice.com
Carbon Nanotubes Could Provide the Military With Battery-Power in Textiles
The carbon fibers can be spooled into strong, conductive thread. Like spider silk, it is stretchy and strong. Credit: Joseph Fuqua II/UC Creative Services
Carbon nanotubes could lead to clothing that can double as a battery, a discovery that could be particularly useful for the military.
A team from the University of Cincinnati—in a partnership with the Wright-Patterson Air force base—are working to take advantage of the properties of carbon nanotubes in developing new applications for soldiers in the field.
“The major challenge is translating these beautiful properties to take advantage of their strength, conductivity and heat resistance,” UC professor Vesselin Shanov, who co-directs UC’s Nanoworld Laboratories, said in a statement.
Graduate student Mark Haase has worked with Air Force researchers over the past year to find applications for carbon nanotubes using X-ray computer tomography to analyze samples.
“This pushes us to work in groups and to specialize,” Haase said in a statement. “These are the same dynamics we see in corporate research and industry. Engineering is a group activity these days so we can take advantage of that.”
The researchers used chemical vapor deposition to grow the carbon nanotubes on silicon wafers the size of a quarter under heat in a vacuum chamber.
“Each particle has a nucleation point,” Haase said. “Colloquially, we can call it a seed. Our carbon-containing gas is introduced into the reactor. When the carbon gas interacts with our ‘seed,’ it breaks down and re-forms on the surface. We let it grow until it reaches the size we want.”
UC’s Nanoworld Lab set a world record in 2007 by growing a nanotube that stretched nearly two centimeters, the longest carbon nanotube array produced in a lab at the time. The lab can currently create nanotubes that are substantially longer.
They were able to stretch the little fibrous square over an industrial spool in the lab to convert the sheet of carbon to a spun thread that can be woven into textiles.
“It’s exactly like a textile,” Shanov said. “We can assemble them like a machine thread and use them in applications ranging from sensors to track heavy metals in water or energy storage devices, including super capacitors and batteries.”
This ultimately could lead to a much lighter load for soldiers in battle.
“As much as one-third of the weight they carry is just batteries to power all of their equipment,” Haase said. “So even if we can shave a little off that, it’s a big advantage for them in the field.”
The study was published in Materials Research Express.
Full article by Kenny Walter – Digital Reporter @RandMagazine here.