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

SBIR Funding Furthers DexMat CNT Technology

Source: Original article appears in the December 2018 issue of the Wire Journal International.
The feature on DexMat is on pages 48-50.

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 Named as SpaceCom Entrepreneur Challenge Semi-Finalist

HOUSTON – SpaceCom – The Space Commerce Conference and Exposition, where NASA, aerospace and industry come together to connect, announces the finalists of the SpaceCom Entrepreneur Challenge. Taking place at the George R. Brown Convention Center in Houston November 27-28, this challenge is the culmination of the SpaceCom Entrepreneur Summit (SES). The Entrepreneur Challenge began with 56 startup applicants. Through the first round of judging, that number was narrowed to 23 and now 17 semi-finalists who will present during the first day of the SpaceCom Entrepreneur Summit, Tuesday, November 27.

The semi-finalists include:

  • Arlula
  • Benchmark Space Systems
  • Cemvita Factory Inc.
  • Devali Inc
  • DexMat, Inc. 
  • EXOS Aerospace Systems & Technologies
  • Finsophy Inc.
  • Hedy-Anthiel Space Systems
  • Lazarus 3D Inc.,
  • Lucid Drone Technologies, Inc.
  • LunaSonde, LLC
  • Molon Labe LLC
  • SaraniaSat Inc.,
  • Solstar Space Company
  • STARK Industries LLC
  • Sugarhouse Aerospace
  • Swift Data LLC

At the culmination of day one, five finalists will be selected to present during a pitch competition. The winner will then be selected after the final round of pitches during the general session November 28 at 1:30 PM. During this presentation, members of the audience and a panel of judges will select the grand prize winner. These finalists are eligible to win the below prizes provided by Google Cloud for Startups:

  •  $100,000 in Google Cloud credits to the competition winner
  • $20,000 in Google Cloud credits for runners up
  • $3,000 in Google Cloud credits for every qualified entrant in the competition

Additional prizes include:

  • Guaranteed extended meeting with an investment firm
  • Speaking role at SpaceCom 2019
  • A booth at SpaceCom 2019

Source: https://spacecomexpo.com/wp-content/uploads/2018/11/SES-Finalists-Press-Release.final_.pdf

DexMat Featured in Wire Journal International

Source: Original article appears in the October 2018 issue of the Wire Journal International.
Free subscription is required to read the digital version of the article. The feature on DexMat is on pages 52-53.

Space Dust Repelling Carbon Nanotube Fibers

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 10-75m 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.

Source: Spacesuit Integrated Carbon Nanotube Dust Removal System: A Scaled Prototype

DexMat Awarded Phase I SBIR: Robust Lightweight CNT Wiring for Space Systems


Abstract: 
NASA is challenged to find ways of effectively shielding sensitive electronic equipment from electromagnetic interference (EMI) without adding significant weight to space flight vehicles and satellites (the heavier they are the more fuel they need to achieve orbit).  EMI shielding for wire and cables is an attractive opportunity for weight reduction. However, with the advent of highly reusable next generation space vehicles, wiring must be not only light weight, but also strong and robust, capable of withstanding extreme conditions, intense vibration and long lifecycles. It is important that wire weight reductions do not come at the expense of mechanical strength or EMI shielding effectiveness.  DexMat is developing a novel and highly conductive Carbon nanotube (CNT) EMI shield product that will allow for significant weight reduction without compromising mechanical strength or shield effectiveness. CNTs are advancing as the most promising solution for reducing the weight of spacecraft wires.  The shielding effectiveness of CNT materials is comparable to that of heavy metal braids, but at a fraction of the weight.  Compared to a copper wire with the same diameter, a CNT fiber has 6 times higher strength, more than 6 times lower density,  and at least 25 times higher flexure tolerance, essential qualities for conductors in aerospace applications. Under this Phase I project, DexMat will develop CNT shielding braid (made from CNT yarn from Dexmat) that can potentially increase the mechanical strength of CNT tape used as a primary EMI shield. These CNT braids will be of different thicknesses and area coverage, to augment the performance and product appeal of CNT tapes. Additionally, DexMat will begin to conduct the first accelerated aging tests to determine the impact on mechanical strength of shielding made with CNT tapes, CNT yard braids, and hybrid CNT tape/braid combinations.

Potential NASA Applications: 
The first planned product to contain DexMat technology is lightweight CNT cables. CNT cables combine high strength, electrical and thermal conductivity with low density, making them ideal for aerospace applications where weight reduction is a priority, including reusable next generation space vehicles and satellites. Given the tremendous costs associated with satellite launches, NASA and the aerospace industry will see substantial savings from our CNT-based wire.

Potential Non-NASA Applications: 
DexMat CNT technology has applications in the military aircraft and commercial aviation markets, to effectively reduce weight of aircraft and satellite designs.  For a single-aisle aircraft, a 1% reduction of in weight can lead to a net cost savings of $240K-$1.6M per year in use. For larger aircraft, the savings can reach $2.4-5M. Additional applications include wearable electronics, eTextiles and bioelectronics.

Carbon Nanotubes Could Provide the Military With Battery-Power in Textiles

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.