CNT Yarn Capacitive Fabric Touch Sensor

DexMat carbon nanotube yarn is conductive, durable, flexible, and lightweight – so naturally, we are excited about its potential to be used in the emerging field of wearable electronics. Because our yarn can be handled like a textile thread, it can potentially be combined together with textile yarns to make clothing with complex electronic functionality without sacrificing comfort or weight. Additionally, because they have such a high surface area, our CNT yarns are excellent at interfacing electrically with the human body, whether that be through contact with body fluids or through “dry” contact with the skin. This means that they can potentially be used to make smart clothing that monitors the health of the wearer, or tracks movement and muscle contraction.

Capacitive touch sensing is a body-to-machine interfacing technology that is already in widespread use in the modern world, and which has a lot of potential in wearable technology – this type of device can be used to fabricate clothing with built-in buttons or even keyboards which operate with the touch of a finger. A basic description of capacitive touch sensing technology can be found here.

With the help of our friends at ZSK, we have made a capacitive touch sensor using DexMat CNT yarn. Check it out in the video below!

The demo consists of a patch of CNT yarn sewn into the backing fabric, with the tail end of that yarn connected to one of the input pins of an Arduino chip. The Arduino can be connected to a computer or other power source via a usb connection, and this connection provides that chip with a “ground” electrical voltage. Touching the CNT yarn with a fingertip shifts the voltage level of the connected input pin away from that ground level, and this triggers a pre-defined response (in this case, lighting up the Arduino LEDs and playing a sound). This works with a very light touch from the finger, and even works with just the single CNT yarn connecting the swatch to the chip – the additional surface area of the CNT yarn fabric patch wasn’t necessary for this particular case, but it also serves as a nice demonstration of how the yarn can be incorporated into a fabric!

The CNT yarn that was used to make this demo was our 200 micron HS yarn, but other yarn sizes should produce similar results. You can order CNT yarn and fiber in a variety of sizes from our online store at store.dexmat.com.

Rice University launches bold climate change initiative with Shell

Rice University has launched a bold climate change initiative with Shell to fundamentally change how the world uses hydrocarbons.

Carbon Hub is a major research initiative to create a zero-emissions future in which oil and natural gas provide both clean energy and advanced materials that help house, move, clothe and feed people.

You can read about the project here.

Space Elevator Kickstarter Project

One of our customers, Dr. Peter Renteln, has recently launched a Kickstarter campaign to fund experiments in methods of mechanically strengthening carbon nanotube yarns.  Dr. Renteln’s ultimate goal is to help bridge the gap between the current performance of carbon nanotube yarns and the type of performance that might one day make a Space Elevator project possible.

DexMat carbon nanotube braid was used for some of the initial testing in this project, and we are always interested to see if methods can be developed that will make our materials even stronger. We are excited to follow this project and see the outcome of these experiments!

You can read about and contribute to the Kickstarter project here.

Carbon Nanotube AUX Cable

In this video, we demonstrate an auxiliary cable made with carbon nanotube (CNT) conductors and shielding. The cable has two CNT yarn conductors that are insulated with a nylon braid and then shielded with a CNT fiber braid. The sound quality is great and highlights the tremendous potential for CNT materials in high-end audio cables!

Flexible CNT Antennas from Rice U

Antennas of flexible nanotube films an alternative for electronics

HOUSTON – (June 10, 2019) – Antennas made of carbon nanotube films are just as efficient as copper for wireless applications, according to researchers at Rice University’s Brown School of Engineering. They’re also tougher, more flexible and can essentially be painted onto devices.

The Rice lab of chemical and biomolecular engineer Matteo Pasquali tested antennas made of “shear-aligned” nanotube films. The researchers discovered that not only were the conductive films able to match the performance of commonly used copper films, they could also be made thinner to better handle higher frequencies.

Metal-free antennas made of thin, strong, flexible carbon nanotube films are as efficient as common copper antennas, according to a new study by Rice University researchers. (Credit: Jeff Fitlow/Rice University)

Metal-free antennas made of thin, strong, flexible carbon nanotube films are as efficient as common copper antennas, according to a new study by Rice University researchers. (Credit: Jeff Fitlow/Rice University)

The results detailed in Applied Physics Letters advance the lab’s previous work on antennas based on carbon nanotube fibers.

The lab’s shear-aligned antennas were tested at the National Institute of Standards and Technology (NIST) facility in Boulder, Colorado, by lead author Amram Bengio, who carried out the research and wrote the paper while earning his doctorate in Pasquali’s lab. Bengio has since founded a company to further develop the material.

At the target frequencies of 5, 10 and 14 gigahertz, the antennas easily held their own with their metal counterparts, he said. “We were going up to frequencies that aren’t even used in Wi-Fi and Bluetooth networks today, but will be used in the upcoming 5G generation of antennas,” he said.

Bengio noted other researchers have argued nanotube-based antennas and their inherent properties have kept them from adhering to the “classical relationship between radiation efficiency and frequency,” but the Rice experiments with more refined films have proved them wrong, allowing for the one-to-one comparisons.

To make the films, the Rice lab dissolved nanotubes, most of them single-walled and up to 8 microns long, in an acid-based solution. When spread onto a surface, the shear force produced prompts the nanotubes to self-align, a phenomenon the Pasquali lab has applied in other studies.

Bengio said that although gas-phase deposition is widely employed as a batch process for trace deposition of metals, the fluid-phase processing method lends itself to more scalable, continuous antenna manufacturing.

The test films were about the size of a glass slide, and between 1 and 7 microns thick. The nanotubes are held together by strongly attractive van der Waals forces, which gives the material mechanical properties far better than those of copper.

The researchers said the new antennas could be suitable for 5G networks but also for aircraft, especially unmanned aerial vehicles, for which weight is a consideration; as wireless telemetry portals for downhole oil and gas exploration; and for future “internet of things” applications.

Rice University alumnus Amram Bengio holds a flexible nanotube film antenna. The antenna, which has proven as efficient as those made of copper wire, can essentially be painted onto devices. (Credit: Jeff Fitlow/Rice University)
Rice University alumnus Amram Bengio holds a flexible nanotube film antenna. The antenna, which has proven as efficient as those made of copper wire, can essentially be painted onto devices. (Credit: Jeff Fitlow/Rice University)

“There are limits because of the physics of how an electromagnetic wave propagates through space,” Bengio said. “We’re not changing anything in that regard. What we are changing is the fact that the material from which all these antennas will be made is substantially lighter, stronger and more resistant to a wider variety of adverse environmental conditions than copper.”

“This is a great example of how collaboration with national labs greatly expands the reach of university groups,” Pasquali said. “We could never have done this work without the intellectual involvement and experimental capabilities of the NIST team.”

Co-authors of the paper are Rice graduate student Lauren Taylor, research group manager Robert Headrick and alumni Michael King and Peiyu Chen; Damir Senic, Charles Little, John Ladbury, Christian Long, Christopher Holloway, Nathan Orloff and James Booth, all of NIST; and former Rice faculty member Aydin Babakhani, now an associate profess or of electrical and computer engineering at UCLA. Pasquali is the A.J. Hartsook Professor of Chemical and Biomolecular Engineering, professor of chemistry and of materials science and nanoengineering. Bengio is the founder and chief operating officer of Wootz, L.L.C.

The Air Force Office of Scientific Research, the Department of Defense and a National Defense Science and Engineering Graduate Fellowship supported the research.

 

Source: Rice University News & Media

Will it Burn? CNT Yarn vs Stainless Steel Thread

This video highlights the high temperature stability of CNT yarns compared to stainless steel thread by applying a 1430 C butane torch to both materials. The stainless steel thread barely lasts 1 second before melting, while the CNT yarn survives the torch for more than 30 seconds without any visible damage.  The high thermal stability and superior thermal conductivity of the CNT material is most likely the reason that it is able to survive exposure to the flame from the torch.  The impressive thermal properties of CNT fibers and films make them highly promising for application in flame retardant materials such as those used in firefighter suits.

DexMat CNT Tape as Lightweight EMI Shielding

In this video we explain how DexMat’s carbon nanotube (CNT) tape has been used to replace the two EMI copper shielding braids typically used in RG316 cables. The performance of DexMat prototypes matches standard RG316 performance, while reducing the total weight of the cable by 50%!

The shielding effectiveness and insertion loss results for the CNT and Cu shielded cables are shown below. The CNT tape shielded cables have the following advantages:

  • Overall RG-316 cable weight reduction of CNT shielded vs. Cu double braid shielded cable without connectors is over 50%
  • CNT tape shield is 100 microns thick compared to 500 micron thick Cu double braid shield
  • Easy to apply CNT tape to coaxial as well as twisted pair type cables
  • Wide range of CNT tape widths and lengths are available for purchase
  • CNT tape shielded cables survive at least 1000 flex cycles with a minimum bend radius of at least 7.5X the jacketed cable diameter

Source: https://dexmat.com/cnt-products/cnt-tape-film/

Specification Sheet: DexMat fiber, tape, and cable specs Dec-2018

DexMat CNT Tape Shielded Cables Offer 50% Weight Reduction

Houston, TX- 12/11/2018. Working in collaboration with Minnesota Wire & Cable Company, DexMat has produced carbon nanotube (CNT) tape shielded RG-316 cables that perform comparably to copper (Cu) double braid shielded RG-316 cables. However, the CNT tape shields are 95% lighter than the copper double braid shields. The shielding effectiveness and insertion loss results for the CNT and Cu shielded cables are shown below. The CNT tape shielded cables have the following advantages:

  • Overall RG-316 cable weight reduction of CNT shielded vs. Cu double braid shielded cable without connectors is over 50%
  • CNT tape shield is 100 microns thick compared to 500 micron thick Cu double braid shield
  • Easy to apply CNT tape to coaxial as well as twisted pair type cables
  • Wide range of CNT tape widths and lengths are available for purchase
  • CNT tape shielded cables survive at least 1000 flex cycles with a minimum bend radius of at least 7.5X the jacketed cable diameter

Source: https://dexmat.com/cnt-products/cnt-tape-film/

Specification Sheet: DexMat fiber, tape, and cable specs Dec-2018

DexMat SpaceCom 5 Minute Pitch

November 28, 2018. Out of the original 17 semi-finalists, DexMat was selected as one of 5 finalists to pitch at the 2018 SpaceCom Entrepreneur Summit in Houston, TX, for the opportunity to win the $100,000 Entrepreneur Challenge. As a runner-up, DexMat won $20,000 in Google Cloud Credits.

Click here for more information on the SpaceCom Entrepreneur Summit.

DexMat Carbon Nanotube Yarn: Will it Burn?

This video highlights the high temperature stability of CNT yarns compared to copper wire by applying a 1430 C butane torch to both materials. The copper wire lasts about 5 seconds before melting, while the CNT yarn survives the torch for more than 30 seconds without any visible damage.  The high thermal stability and superior thermal conductivity of the CNT material is most likely the reason that it is able to survive exposure to the flame from the torch.  The impressive thermal properties of CNT fibers and films make them highly promising for application in flame retardant materials such as those used in firefighter suits.