Tag Archives: e-textiles

MXene-coated yarn for wearable electronics

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There’s been a lot of talk about wearable electronics, specifically e-textiles, but nothing seems to have entered the marketplace. Scaling up your lab discoveries for industrial production can be quite problematic. From an October 10, 2019 news item on ScienceDaily,

Producing functional fabrics that perform all the functions we want, while retaining the characteristics of fabric we’re accustomed to is no easy task.

Two groups of researchers at Drexel University — one, who is leading the development of industrial functional fabric production techniques, and the other, a pioneer in the study and application of one of the strongest, most electrically conductive super materials in use today — believe they have a solution.

They’ve improved a basic element of textiles: yarn. By adding technical capabilities to the fibers that give textiles their character, fit and feel, the team has shown that it can knit new functionality into fabrics without limiting their wearability.

…

An October 10, 2019 Drexel University news release (also on EurekAlert), which originated the news item, details the proposed solution (pun! as you’ll see in the video following this excerpt),

In a paper recently published in the journal Advanced Functional Materials, the researchers, led by Yury Gogotsi, PhD, Distinguished University and Bach professor in Drexel’s College of Engineering, and Genevieve Dion, an associate professor in Westphal College of Media Arts & Design and director of Drexel’s Center for Functional Fabrics, showed that they can create a highly conductive, durable yarn by coating standard cellulose-based yarns with a type of conductive two-dimensional material called MXene.

Hitting snags

“Current wearables utilize conventional batteries, which are bulky and uncomfortable, and can impose design limitations to the final product,” they write. “Therefore, the development of flexible, electrochemically and electromechanically active yarns, which can be engineered and knitted into full fabrics provide new and practical insights for the scalable production of textile-based devices.”

The team reported that its conductive yarn packs more conductive material into the fibers and can be knitted by a standard industrial knitting machine to produce a textile with top-notch electrical performance capabilities. This combination of ability and durability stands apart from the rest of the functional fabric field today.

Most attempts to turn textiles into wearable technology use stiff metallic fibers that alter the texture and physical behavior of the fabric. Other attempts to make conductive textiles using silver nanoparticles and graphene and other carbon materials raise environmental concerns and come up short on performance requirements. And the coating methods that are successfully able to apply enough material to a textile substrate to make it highly conductive also tend to make the yarns and fabrics too brittle to withstand normal wear and tear.

“Some of the biggest challenges in our field are developing innovative functional yarns at scale that are robust enough to be integrated into the textile manufacturing process and withstand washing,” Dion said. “We believe that demonstrating the manufacturability of any new conductive yarn during experimental stages is crucial. High electrical conductivity and electrochemical performance are important, but so are conductive yarns that can be produced by a simple and scalable process with suitable mechanical properties for textile integration. All must be taken into consideration for the successful development of the next-generation devices that can be worn like everyday garments.”

The winning combination

Dion has been a pioneer in the field of wearable technology, by drawing on her background on fashion and industrial design to produce new processes for creating fabrics with new technological capabilities. Her work has been recognized by the Department of Defense, which included Drexel, and Dion, in its Advanced Functional Fabrics of America effort to make the country a leader in the field.

She teamed with Gogotsi, who is a leading researcher in the area of two-dimensional conductive materials, to approach the challenge of making a conductive yarn that would hold up to knitting, wearing and washing.

Gogotsi’s group was part of the Drexel team that discovered highly conductive two-dimensional materials, called MXenes, in 2011 and have been exploring their exceptional properties and applications for them ever since. His group has shown that it can synthesize MXenes that mix with water to create inks and spray coatings without any additives or surfactants – a revelation that made them a natural candidate for making conductive yarn that could be used in functional fabrics. [Gogotsi’s work was featured here in a May 6, 2019 posting]

“Researchers have explored adding graphene and carbon nanotube coatings to yarn, our group has also looked at a number of carbon coatings in the past,” Gogotsi said. “But achieving the level of conductivity that we demonstrate with MXenes has not been possible until now. It is approaching the conductivity of silver nanowire-coated yarns, but the use of silver in the textile industry is severely limited due to its dissolution and harmful effect on the environment. Moreover, MXenes could be used to add electrical energy storage capability, sensing, electromagnetic interference shielding and many other useful properties to textiles.”

In its basic form, titanium carbide MXene looks like a black powder. But it is actually composed of flakes that are just a few atoms thick, which can be produced at various sizes. Larger flakes mean more surface area and greater conductivity, so the team found that it was possible to boost the performance of the yarn by infiltrating the individual fibers with smaller flakes and then coating the yarn itself with a layer of larger-flake MXene.

Putting it to the test

The team created the conductive yarns from three common, cellulose-based yarns: cotton, bamboo and linen. They applied the MXene material via dip-coating, which is a standard dyeing method, before testing them by knitting full fabrics on an industrial knitting machine – the kind used to make most of the sweaters and scarves you’ll see this fall.

Each type of yarn was knit into three different fabric swatches using three different stitch patterns – single jersey, half gauge and interlock – to ensure that they are durable enough to hold up in any textile from a tightly knit sweater to a loose-knit scarf.

“The ability to knit MXene-coated cellulose-based yarns with different stitch patterns allowed us to control the fabric properties, such as porosity and thickness for various applications,” the researchers write.

To put the new threads to the test in a technological application, the team knitted some touch-sensitive textiles – the sort that are being explored by Levi’s and Yves Saint Laurent as part of Google’s Project Jacquard.

Not only did the MXene-based conductive yarns hold up against the wear and tear of the industrial knitting machines, but the fabrics produced survived a battery of tests to prove its durability. Tugging, twisting, bending and – most importantly – washing, did not diminish the touch-sensing abilities of the yarn, the team reported – even after dozens of trips through the spin cycle.

Pushing forward

But the researchers suggest that the ultimate advantage of using MXene-coated conductive yarns to produce these special textiles is that all of the functionality can be seamlessly integrated into the textiles. So instead of having to add an external battery to power the wearable device, or wirelessly connect it to your smartphone, these energy storage devices and antennas would be made of fabric as well – an integration that, though literally seamed, is a much smoother way to incorporate the technology.

“Electrically conducting yarns are quintessential for wearable applications because they can be engineered to perform specific functions in a wide array of technologies,” they write.

Using conductive yarns also means that a wider variety of technological customization and innovations are possible via the knitting process. For example, “the performance of the knitted pressure sensor can be further improved in the future by changing the yarn type, stitch pattern, active material loading and the dielectric layer to result in higher capacitance changes,” according to the authors.

Dion’s team at the Center for Functional Fabrics is already putting this development to the test in a number of projects, including a collaboration with textile manufacturer Apex Mills – one of the leading producers of material for car seats and interiors. And Gogotsi suggests the next step for this work will be tuning the coating process to add just the right amount of conductive MXene material to the yarn for specific uses.

“With this MXene yarn, so many applications are possible,” Gogotsi said. “You can think about making car seats with it so the car knows the size and weight of the passenger to optimize safety settings; textile pressure sensors could be in sports apparel to monitor performance, or woven into carpets to help connected houses discern how many people are home – your imagination is the limit.”

Researchers have produced a video about their work,

Here’s a link to and a citation for the paper,

Knittable and Washable Multifunctional MXene‐Coated Cellulose Yarns by Simge Uzun, Shayan Seyedin, Amy L. Stoltzfus, Ariana S. Levitt, Mohamed Alhabeb, Mark Anayee, Christina J. Strobel, Joselito M. Razal, Genevieve Dion, Yury Gogotsi. Advanced Functional Materials DOI: https://doi.org/10.1002/adfm.201905015 First published: 05 September 2019

This paper is behind a paywall.

Computers made of gold embroidery and an Organic Bioelectronics conference (ORBITALY) in Naples, Italy

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Spend enough time reading about emerging technologies and, at some point, you will find yourself questioning some of your dearly held beliefs. It gives a whole new meaning to term, mind altering (also, mind blowing or mind expanding), which in the 1960s was used to refer to the effects of LSD and other hallucinogens. Today <September 1, 2019 (Labour Day in Canada and elsewhere), I have two news bits that could be considered mind expanding, sans hallucinogens.

Gold-embroidered computers

The Embroidered Computer. Artists: Irene Posch and Ebru Kurbak .[downloaded from http://www.ireneposch.net/the-embroidered-computer/]

If you look closely, you’ll see the beads shift position and that’s how the ones and zeroes make themselves known on this embroidered computer. An August 23, 2019 article (updated from a March 8, 2019 article) on the CBC’s (Canadian Broadcasting Corporation) Radio, Spark programme web space, provides insight into the work,

A beautiful ’embroidered computer’ may explode our categories of what computers are supposed to look like.

After all, we may think the design of a computer is permanent, but what a computer ‘looks like’ depends a lot on what era it’s from.

…

“We use gold-coloured copper wire to form a coil, in a donut shape” Posch told Spark host Nora Young. “Then we have a magnetic bead that sits in the middle of this coil, and when this coil is [connected to] power, the magnetic bead is either attracted or pushed away….

Depending on how we power… the embroidered coil, we can direct the magnetic bead in different positions.”

More gold embroidery on top of the bead will flip one way or another, based on the bead [above].

The process is analogous to the zeros and ones of computation.

As well as being an artist, Posch is a professor at the University for Art and Industrial Design in Linz, Austria. Much of her work and research uses textile art to explore digital technology.

In this case, it’s not like Irene expects people to start doing today’s heavy-duty computing on a two-metre-long, eight-bit golden embroidered fabric computer. But The Embroidered Computer project opens up space to question the design of computers in particular, but also our technologies in general

“I understand The Embroidered Computer as an alternative, as an example, but also a critique of what we assume a computer to be today, and how it technically could be different,” Posch said. “If this is actually what we want is a whole different question, but I think it’s interesting to propose an alternative.”

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Bringing together textiles and electronics, which are normally seen as worlds apart, can bring new insights. “Going into the history of computing we very soon become aware that they’re not that apart as we sometimes think they are, if you think of the Jacquard weaving loom as one of the predecessors of computing today.”

You can find our more about the artists (Ebru Kurkak here) and (Irene Posch here). Finally, you can hear the Spark radio interview with Irene Posch here.

ORBITALY 2019

I don’t have a lot of information about this event but what I do have looks intriguing. From the ORBITALY 2019 conference home page,

OrBItaly (Organic BIoelectronics Italy) is an international conference, organized by the Italian Scientific Community and attended by scientists of the highest reputation, dedicated to the most recent results in the field of bioelectronics, with a particular focus on the employment of organic materials.

OrBItaly has attracted in the years a growing interest by scientists coming from all over the world. The 2019 edition is the fifth one of this cross-disciplinary conference, and will be held in Naples, on October 21st-23rd, 2019, at the Congress Center of the University Federico II

This year the conference will be preceded by the first edition of the Graduate School in Organic Bioelectronics, that will be held at the Congress Center of the University of Naples Federico II in Naples (Italy), on October 20th, 2019. The school is mainly targeted to PhD students, post-docs and young researchers as well as to senior scientists and industry-oriented researchers, giving them the opportunity to attend an overview of the latest advances in the fields of organic bioelectronics presented by leading scientists of the highest international repute. Invited lecturers will provide highly stimulating lessons at advanced levels in their own field of research, and closely interact with the attendees during platform discussions, outreach events and informal meetings.

Organizing Committee

Mario Barra, CNR – SPIN, mario.barra@spin.cnr.it
Irene Bonadies, CNR – IPCB, irene.bonadies@ipcb.cnr.it
Antonio Cassinese, Univ. Napoli Federico II, cassinese@na.infn.it
Valeria Criscuolo, IIT, valeria.criscuolo@iit.it
Claudia Lubrano, IIT, claudia.lubrano@iit.it
Maria Grazia Maglione, ENEA, mariagrazia.maglione@enea.it
Paola Manini, Univ. Napoli Federico II, paola.manini@unina.it
Alessandro Pezzella, Univ. Napoli Federico II, alessandro.pezzella@unina.it
Maria Grazia Raucci, CNR – IPCB, mariagrazia.raucci@cnr.it
Francesca Santoro, IIT, francesca.santoro@iit.it
Paolo Tassini, ENEA, paolo.tassini@enea.it

So, the conference runs from the 21st to the 23rd of October 2019 and there’s a one-day graduate school programme being held one day prior to the conference on the 20th of October 2019.

Regular readers may notice that some of the ORBITALY 2019 organizers have recently been mentioned here in an August 25, 2019 posting titled, Cyborgs based on melanin circuits.

Embroidering electronics into clothing

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Researchers at The Ohio State University are developing embroidered antennas and circuits with 0.1 mm precision—the perfect size to integrate electronic components such as sensors and computer memory devices into clothing. Photo by Jo McCulty, courtesy of The Ohio State University.

Researchers at The Ohio State University are developing embroidered antennas and circuits with 0.1 mm precision—the perfect size to integrate electronic components such as sensors and computer memory devices into clothing. Photo by Jo McCulty, courtesy of The Ohio State University.

An April 13, 2016 news item on Nanowerk describes an advance in the field of wearable electronics,

Researchers who are working to develop wearable electronics have reached a milestone: They are able to embroider circuits into fabric with 0.1 mm precision—the perfect size to integrate electronic components such as sensors and computer memory devices into clothing.

With this advance, the Ohio State University researchers have taken the next step toward the design of functional textiles—clothes that gather, store, or transmit digital information. With further development, the technology could lead to shirts that act as antennas for your smart phone or tablet, workout clothes that monitor your fitness level, sports equipment that monitors athletes’ performance, a bandage that tells your doctor how well the tissue beneath it is healing—or even a flexible fabric cap that senses activity in the brain.

That last item is one that John Volakis, director of the ElectroScience Laboratory at Ohio State, and research scientist Asimina Kiourti are investigating. The idea is to make brain implants, which are under development to treat conditions from epilepsy to addiction, more comfortable by eliminating the need for external wiring on the patient’s body.

An April 13, 2016 Ohio State University news release by Pam Frost Gorder, which originated the news item, expands on the theme (Note: Links have been removed),

“A revolution is happening in the textile industry,” said Volakis, who is also the Roy & Lois Chope Chair Professor of Electrical Engineering at Ohio State. “We believe that functional textiles are an enabling technology for communications and sensing—and one day even medical applications like imaging and health monitoring.”

Recently, he and Kiourti refined their patented fabrication method to create prototype wearables at a fraction of the cost and in half the time as they could only two years ago. With new patents pending, they published the new results in the journal IEEE Antennas and Wireless Propagation Letters.

In Volakis’ lab, the functional textiles, also called “e-textiles,” are created in part on a typical tabletop sewing machine—the kind that fabric artisans and hobbyists might have at home. Like other modern sewing machines, it embroiders thread into fabric automatically based on a pattern loaded via a computer file. The researchers substitute the thread with fine silver metal wires that, once embroidered, feel the same as traditional thread to the touch.

“We started with a technology that is very well known—machine embroidery—and we asked, how can we functionalize embroidered shapes? How do we make them transmit signals at useful frequencies, like for cell phones or health sensors?” Volakis said. “Now, for the first time, we’ve achieved the accuracy of printed metal circuit boards, so our new goal is to take advantage of the precision to incorporate receivers and other electronic components.”

The shape of the embroidery determines the frequency of operation of the antenna or circuit, explained Kiourti.

The shape of one broadband antenna, for instance, consists of more than half a dozen interlocking geometric shapes, each a little bigger than a fingernail, that form an intricate circle a few inches across. Each piece of the circle transmits energy at a different frequency, so that they cover a broad spectrum of energies when working together—hence the “broadband” capability of the antenna for cell phone and internet access.

“Shape determines function,” she said. “And you never really know what shape you will need from one application to the next. So we wanted to have a technology that could embroider any shape for any application.”

The researchers’ initial goal, Kiourti added, was just to increase the precision of the embroidery as much as possible, which necessitated working with fine silver wire. But that created a problem, in that fine wires couldn’t provide as much surface conductivity as thick wires. So they had to find a way to work the fine thread into embroidery densities and shapes that would boost the surface conductivity and, thus, the antenna/sensor performance.

Previously, the researchers had used silver-coated polymer thread with a 0.5-mm diameter, each thread made up of 600 even finer filaments twisted together. The new threads have a 0.1-mm diameter, made with only seven filaments. Each filament is copper at the center, enameled with pure silver.

They purchase the wire by the spool at a cost of 3 cents per foot; Kiourti estimated that embroidering a single broadband antenna like the one mentioned above consumes about 10 feet of thread, for a material cost of around 30 cents per antenna. That’s 24 times less expensive than when Volakis and Kiourti created similar antennas in 2014.

In part, the cost savings comes from using less thread per embroidery. The researchers previously had to stack the thicker thread in two layers, one on top of the other, to make the antenna carry a strong enough electrical signal. But by refining the technique that she and Volakis developed, Kiourti was able to create the new, high-precision antennas in only one embroidered layer of the finer thread. So now the process takes half the time: only about 15 minutes for the broadband antenna mentioned above.

She’s also incorporated some techniques common to microelectronics manufacturing to add parts to embroidered antennas and circuits.

One prototype antenna looks like a spiral and can be embroidered into clothing to improve cell phone signal reception. Another prototype, a stretchable antenna with an integrated RFID (radio-frequency identification) chip embedded in rubber, takes the applications for the technology beyond clothing. (The latter object was part of a study done for a tire manufacturer.)

Yet another circuit resembles the Ohio State Block “O” logo, with non-conductive scarlet and gray thread embroidered among the silver wires “to demonstrate that e-textiles can be both decorative and functional,” Kiourti said.

They may be decorative, but the embroidered antennas and circuits actually work. Tests showed that an embroidered spiral antenna measuring approximately six inches across transmitted signals at frequencies of 1 to 5 GHz with near-perfect efficiency. The performance suggests that the spiral would be well-suited to broadband internet and cellular communication.

In other words, the shirt on your back could help boost the reception of the smart phone or tablet that you’re holding – or send signals to your devices with health or athletic performance data.

The work fits well with Ohio State’s role as a founding partner of the Advanced Functional Fabrics of America Institute, a national manufacturing resource center for industry and government. The new institute, which joins some 50 universities and industrial partners, was announced earlier this month by U.S. Secretary of Defense Ashton Carter.

Syscom Advanced Materials in Columbus provided the threads used in Volakis and Kiourti’s initial work. The finer threads used in this study were purchased from Swiss manufacturer Elektrisola. The research is funded by the National Science Foundation, and Ohio State will license the technology for further development.

Until then, Volakis is making out a shopping list for the next phase of the project.

“We want a bigger sewing machine,” he said.

Here’s a link to and a citation for the paper,

Fabrication of Textile Antennas and Circuits With 0.1 mm Precision by A. Kiourti, C. Lee, and J. L. Volakis.  IEEE Antennas and Wireless Propagation Letters (Volume:15 ) Page(s): 151 – 153 ISSN : 1536-1225 INSPEC Accession Number: 15785288 DOI: 10.1109/LAWP.2015.2435257 Date of Publication: 20 May 2015 Issue Date: 2016

This paper is behind a paywall.

Shape memory in a supercapacitor fibre for ‘smart’ textiles (wearable tech: 1 of 3)

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Wearable technology seems to be quite trendy for a grouping not usually seen: consumers, fashion designers, medical personnel, manufacturers, and scientists.

The first in this informal series concerns a fibre with memory shape. From a Nov. 19, 2015 news item on Nanowerk (Note: A link has been removed),

Wearing your mobile phone display on your jacket sleeve or an EKG probe in your sports kit are not off in some distant imagined future. Wearable “electronic textiles” are on the way. In the journal Angewandte Chemie (“A Shape-Memory Supercapacitor Fiber”), Chinese researchers have now introduced a new type of fiber-shaped supercapacitor for energy-storage textiles. Thanks to their shape memory, these textiles could potentially adapt to different body types: shapes formed by stretching and bending remain “frozen”, but can be returned to their original form or reshaped as desired.

A Nov. 19, 2015 Wiley Publishers press release, which originated the news item, provides context and detail about the work,

Any electronic components designed to be integrated into textiles must be stretchable and bendable. This is also true of the supercapacitors that are frequently used for data preservation in static storage systems (SRAM). SRAM is a type of storage that holds a small amount of data that is rapidly retrievable. It is often used for caches in processors or local storage on chips in devices whose data must be stored for long periods without a constant power supply. Some time ago, a team headed by Huisheng Peng at Fudan University developed stretchable, pliable fiber-shaped supercapacitors for integration into electronic textiles. Peng and his co-workers have now made further progress: supercapacitor fibers with shape memory.

Any electronic components designed to be integrated into textiles must be stretchable and bendable. This is also true of the supercapacitors that are frequently used for data preservation in static storage systems (SRAM). SRAM is a type of storage that holds a small amount of data that is rapidly retrievable. It is often used for caches in processors or local storage on chips in devices whose data must be stored for long periods without a constant power supply.
Some time ago, a team headed by Huisheng Peng at Fudan University developed stretchable, pliable fiber-shaped supercapacitors for integration into electronic textiles. Peng and his co-workers have now made further progress: supercapacitor fibers with shape memory.

The fibers are made using a core of polyurethane fiber with shape memory. This fiber is wrapped with a thin layer of parallel carbon nanotubes like a sheet of paper. This is followed by a coating of electrolyte gel, a second sheet of carbon nanotubes, and a final layer of electrolyte gel. The two layers of carbon nanotubes act as electrodes for the supercapacitor. Above a certain temperature, the fibers produced in this process can be bent as desired and stretched to twice their original length. The new shape can be “frozen” by cooling. Reheating allows the fibers to return to their original shape and size, after which they can be reshaped again. The electrochemical performance is fully maintained through all shape changes.

Weaving the fibers into tissues results in “smart” textiles that could be tailored to fit the bodies of different people. This could be used to make precisely fitted but reusable electronic monitoring systems for patients in hospitals, for example. The perfect fit should render them both more comfortable and more reliable.

Here’s a link to and a citation for the paper,

A Shape-Memory Supercapacitor Fiber by Jue Deng, Ye Zhang, Yang Zhao, Peining Chen, Dr. Xunliang Cheng, & Prof. Dr. Huisheng Peng. Angewandte Chemie International Edition  DOI: 10.1002/anie.201508293  First published: 3 November 2015

This paper is behind a paywall.

Fully textile-embedded transparent and flexible technology?

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There are a lot of research teams jockeying for position in the transparent, flexible electrodes stakes (for anyone unfamiliar with the slang, I’m comparing the competition between various research teams to a horse race). A May 11, 2015 news item on Nanowerk describes work from an international collaboration at the University of Exeter (UK), Note: A link has been removed,

An international team of scientists, including Professor Monica Craciun from the University of Exeter, have pioneered a new technique to embed transparent, flexible graphene electrodes into fibres commonly associated with the textile industry.

The discovery could revolutionise the creation of wearable electronic devices, such as clothing containing computers, phones and MP3 players, which are lightweight, durable and easily transportable.

The international collaborative research, which includes experts from the Centre for Graphene Science at the University of Exeter, the Institute for Systems Engineering and Computers, Microsystems and Nanotechnology (INESC-MN) in Lisbon, the Universities of Lisbon and Aveiro in Portugal and the Belgian Textile Research Centre (CenTexBel), is published in the leading scientific journal Scientific Reports (“Transparent conductive graphene textile fibers”).

A May 11, 2015 University of Exeter press release (also on EurekAlert*), which originated the news item,  describes the current situation regarding transparent and flexible electrodes in textiles and how the research at Exeter improves the situation,

Professor Craciun, co-author of the research said: “This is a pivotal point in the future of wearable electronic devices. The potential has been there for a number of years, and transparent and flexible electrodes are already widely used in plastics and glass, for example. But this is the first example of a textile electrode being truly embedded in a yarn. The possibilities for its use are endless, including textile GPS systems, to biomedical monitoring, personal security or even communication tools for those who are sensory impaired.  The only limits are really within our own imagination.”

At just one atom thick, graphene is the thinnest substance capable of conducting electricity. It is very flexible and is one of the strongest known materials. The race has been on for scientists and engineers to adapt graphene for the use in wearable electronic devices in recent years.

This new research has identified that ‘monolayer graphene’, which has exceptional electrical, mechanical and optical properties, make it a highly attractive proposition as a transparent electrode for applications in wearable electronics. In this work graphene was created by a growth method called chemical vapour deposition (CVD) onto copper foil, using a state-of-the-art nanoCVD system recently developed by Moorfield.

The collaborative team established a technique to transfer graphene from the copper foils to a polypropylene fibre already commonly used in the textile industry.

Dr Helena Alves who led the research team from INESC-MN and the University of Aveiro said: “The concept of wearable technology is emerging, but so far having fully textile-embedded transparent and flexible technology is currently non-existing. Therefore, the development of processes and engineering for the integration of graphene in textiles would give rise to a new universe of commercial applications. “

Dr Ana Neves, Associate Research Fellow in Prof Craciun’s team from Exeter’s Engineering Department and former postdoctoral researcher at INESC added: “We are surrounded by fabrics, the carpet floors in our homes or offices, the seats in our cars, and obviously all our garments and clothing accessories. The incorporation of electronic devices on fabrics would certainly be a game-changer in modern technology.

“All electronic devices need wiring, so the first issue to be address in this strategy is the development of conducting textile fibres while keeping the same aspect, comfort and lightness. The methodology that we have developed to prepare transparent and conductive textile fibres by coating them with graphene will now open way to the integration of electronic devices on these textile fibres.”

Dr Isabel De Schrijver,an expert of smart textiles from CenTexBel said: “Successful manufacturing of wearable electronics has the potential for a disruptive technology with a wide array of potential new applications. We are very excited about the potential of this breakthrough and look forward to seeing where it can take the electronics industry in the future.”

Professor Saverio Russo, co-author and also from the University of Exeter, added: “This breakthrough will also nurture the birth of novel and transformative research directions benefitting a wide range of sectors ranging from defence to health care. “

In 2012 Professor Craciun and Professor Russo, from the University of Exeter’s Centre for Graphene Science, discovered GraphExeter – sandwiched molecules of ferric chloride between two graphene layers which makes a whole new system that is the best known transparent material able to conduct electricity.  The same team recently discovered that GraphExeter is also more stable than many transparent conductors commonly used by, for example, the display industry.

Here’s a link to and a citation for the paper,

Electron transport of WS2 transistors in a hexagonal boron nitride dielectric environment by Freddie Withers, Thomas Hardisty Bointon, David Christopher Hudson, Monica Felicia Craciun, & Saverio Russo. Scientific Reports 4, Article number: 4967 doi:10.1038/srep04967 Published 15 May 2014

Did they wait a year to announce the research or is this a second-go-round? In any event, it is an open access paper.

* Added EurekAlert link 1120 hours PDT on May 12, 2015.

‘Silverized’ clothing and wearable electronics

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A July 30, 2013 news item on ScienceDaily features a technique for printing silver directly onto fibres,

Scientists at the National Physical Laboratory (NPL), the UK’s National Measurement Institute, have developed a way to print silver directly onto fibres. This new technique could make integrating electronics into all types of clothing simple and practical. This has many potential applications in sports, health, medicine, consumer electronics and fashion.

Most current plans for wearable electronics require weaving conductive materials into fabrics, which offer limited flexibility and can only be achieved when integrated into the design of the clothing from the start. [emphasis mine] NPL’s technique could allow lightweight circuits to be printed directly onto complete garments.

The July 30, 2013 National Physical Laboratory news release on EurekAlert, which originated the news item, provides a little more detail,

Silver coated fibres created using this technique are flexible and stretchable, meaning circuits can be easily printed onto many different types of fabric, including wool which is knitted in tight loops.

The technique involves chemically bonding a nano‐silver layer onto individual fibres to a thickness of 20 nm. The conductive silver layer fully encapsulates fibres and has good adhesion and excellent conductivity.

The researchers don’t appear to have published a paper but there is a bit more information on the NPL’s Smart Textiles webpage,

At NPL the Electronics Interconnection group has developed a new method to produce conductive textiles. This new technique could make integrating electronics into all types of clothing simple and practical by enabling lightweight circuits to be printed directly onto complete garments.

The nano silver material is chemically bonded to the fabric, encapsulating the fibres and providing full coverage. The resulting textile demonstrates good adhesion, flexibility and is stretchable achieving excellent resistivity of 0.2 Ω/sq.

My May 9, 2012 posting concerns a project where batteries were being woven into textiles for the US military.

Bake and shake your t-shirt to make a flexible electronic device

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I don’t think you actually need to shake but you do need to bake your cotton t-shirt, albeit in a special way, to create a wearable battery  or so the University of South Carolina’s Xiaodong Li says. Excerpted from the June 29, 2012 news item on Nanowerk,

Over the years, the telephone has gone mobile, from the house to the car to the pocket. The University of South Carolina’s Xiaodong Li envisions even further integration of the cell phone – and just about every electronic gadget, for that matter – into our lives.

…

“We wear fabric every day,” said Li, a professor of mechanical engineering at USC. “One day our cotton T-shirts could have more functions; for example, a flexible energy storage device that could charge your cell phone or your iPad.”

Li is helping make the vision a reality. He and post-doctoral associate Lihong Bao have just reported in the journal Advanced Materials (“Towards Textile Storage from Cotton T-Shirts”) how to turn the material in a cotton T-shirt into a source of electrical power.

I’ve been following the ‘wearable battery’ story for a while (the May 9, 2012 posting is the most recent) but Li’s approach is a little different.  Excerpted from the June 29, 2012 University of South Caroline news release by Steven Powell,

Starting with a T-shirt from a local discount store, Li’s team soaked it in a solution of fluoride, dried it and baked it at high temperature. They excluded oxygen in the oven to prevent the material from charring or simply combusting.

The surfaces of the resulting fibers in the fabric were shown by infrared spectroscopy to have been converted from cellulose to activated carbon. Yet the material retained flexibility; it could be folded without breaking.

“We will soon see roll-up cell phones and laptop computers on the market,” Li said. “But a flexible energy storage device is needed to make this possible.”

The once-cotton T-shirt proved to be a repository for electricity. By using small swatches of the fabric as an electrode, the researchers showed that the flexible material, which Li’s team terms activated carbon textile, acts as a capacitor. Capacitors are components of nearly every electronic device on the market, and they have the ability to store electrical charge.

Here’s what makes the approach different; it’s ‘green’ according to Powell’s news release,

Li is particularly pleased to have improved on the means by which activated carbon fibers are usually obtained. “Previous methods used oil or environmentally unfriendly chemicals as starting materials,” he said. “Those processes are complicated and produce harmful side products. Our method is a very inexpensive, green process.”

Somehow I’ve always seen ‘wearable batteries and/or electronics’ as opportunities for electrocution but I seem to be alone with this fear as there’s never any discussion about the safety issues might arise.

ETA July 3, 2012: Dexter Johnson in his June 29, 2012 posting on Nanoclast (a blog on the IEEE [Institute of Electrical and Electronics Engineers] website) notes that the simplicity of Li’s process may be specially exciting,

While Li makes mention of the environmentally friendly chemicals used to impart this capability to a t-shirt, it is perhaps the simplicity of the process that will likely be the most intriguing aspect to manufacturers.

Charged up t-shirts

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There’s been a lot of talk about using t-shirts and other clothing to recharge telephones and other electronic devices but until now everything has been confined to the lab (as per my January 22, 2010 posting [scroll down about1/3 of the way] and my Feb. 15, 2010 posting). The latest edition of the Glastonbury Music Festival in the UK saw the introduction of Sound Charge, a t-shirt that harvests energy from ambient sound to recharge mobile phone batteries.

Here’s how Orange, the telecommunications company behind the Glastonbury experiment did it (from the Orange June 20, 2011 news release,

Following months of planning and development, the prototype, named the Orange ‘Sound Charge’ has been produced in conjunction with renewable energy experts at GotWind. The eco charging device uses an existing technology in a revolutionary way; by reversing the use of a product called Piezoelectric film, allowing people to charge their mobile phones whilst enjoying their favourite headline act at Glastonbury.

Usually found in modern hi-fi speakers, an A4 panel of the modified film is housed inside a t-shirt which then acts much like an oversized microphone by ‘absorbing’ invisible sound pressure waves. These sound waves are converted via the compression of interlaced quartz crystals into an electrical charge, which is fed into an integral reservoir battery that in turn charges most makes and models of mobile phone. As the ‘device’ is worn, a steady charge is able to be dispensed into the phone via a simple interchangeable lead which fits most handsets.

Thankfully given the nature of human sweat and dirt, the film is removable allowing the t-shirt to be cleaned and leaving the components unharmed.

Schematic for Sound Charge t-shirt prototype tested at 2011 Glastonbury Music Festival

As for how efficiently the t-shirts harvest energy and transform it to an electrical charge, there’s still work to be done. From the June 20, 2011 article by Caleb Cox for The Register,

Apparently over the course of a weekend, the T-shirt will only produce enough energy for roughly a single smartphone recharge, so it will probably follow in the footsteps of the wellies by remaining a non-commercial product.

This is not the first joint project between Orange and GotWind, last year they collaborated on ‘rechargeable wellies’ (wellies are rubber boots) for the Glastonbury Festival.

Carbon nanotubes the natural way; weaving carbon nanotubes into heaters; how designers think; robotic skin

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Today I’ll be focusing, in a very mild way, on carbon nanotubes. First, a paper in Astrophysical Journal Letters (Feb. 2010 issue) titled, The Formation of Graphite Whiskers in the  Primitive Solar Nebula, is where an international team of scientists have shared an intriguing discovery about carbon nanotubes. From the news item on physorg.com,

Space apparently has its own recipe for making carbon nanotubes, one of the most intriguing contributions of nanotechnology here on Earth, and metals are conspicuously missing from the list of ingredients.

…

[Joesph] Nuth’s team [based at NASA’s Goddard Space Flight Center] describes the modest chemical reaction. Unlike current methods for producing carbon nanotubes—tiny yet strong structures with a range of applications in electronics and, ultimately, perhaps even medicine—the new approach does not need the aid of a metal catalyst. “Instead, nanotubes were produced when graphite dust particles were exposed to a mixture of carbon monoxide and hydrogen gases,” explains Nuth.

…

The structure of the carbon nanotubes produced in these experiments was determined by Yuki Kimura, a materials scientist at Tohoku University, Japan, who examined the samples under a powerful transmission electron microscope. He saw particles on which the original smooth graphite gradually morphed into an unstructured region and finally to an area rich in tangled hair-like masses. A closer look with an even more powerful microscope showed that these tendrils were in fact cup-stacked carbon nanotubes, which resemble a stack of Styrofoam cups with the bottoms cut out.

Since metals are used as catalysts for creating carbon nanotubes, this discovery hints at the possibility of a ‘greener’ process. In conjunction with the development at McGill (mentioned on this blog here) for making chemical reactions greener by using new nonmetallic catalysts, there may be some positive environmental impacts due to nanotechnology.

Meanwhile here on earth, there’s another new carbon nanotube development and this time it has to do with the material’s conductivity. From the news item on Nanowerk,

An interesting development using multifilament yarns is a new fabric heater made by weaving CNTEC® conductive yarns from Kuraray Living Co., Ltd. This fabric generates heat homogeneously all over the surface because of its outstanding conductivity and is supposed to be the first commercial use of Baytubes® CNTs from Bayer MaterialScience in the Japanese market.

The fabric heater is lightweight and thin, compact and shows a long-lasting bending resistance. It can be used for instance for car seats, household electrical appliances, for heating of clothes and as an anti-freezing material. Tests revealed that it may for example be installed in the water storage tank of JR Hokkaido’s “Ryuhyo-Norokko” train. Inside this train the temperature drops to around -20 °C in wintertime, because so far no heating devices other than potbelly stoves are available. According to JR Hokkaido railway company the fabric heater performed well in preventing the water from freezing. A seat heating application of the fabric heater is still on trial on another JR Hokkaido train line. It is anticipated that the aqueous dispersions might as well be suitable for the compounding of various kinds of materials.

I sometimes suspect that these kinds of nanotechnology-enabled applications are going to change the world in such a fashion that our ancestors (assuming we survive disasters) will be able to understand us only dimly. The closest analogy I have is with Chaucer. An English-speaker trying to read The Canterbury Tales in the language that Chaucer used to write, Middle English, needs to learn an unfamiliar language.

On a completely different topic, Cliff Kuang at Fast Company has written an item on designers and the Myer-Briggs personality test (industrial designer Michael Roller’s website with his data),

Designers love to debate about what personality type makes for the best designer. So Michael Roller took the extra step of getting a bunch of designers to take the Myers Briggs personality test, and published the results …

In other words, designers are less akin to the stereotypical touchy-feely artist, and more like engineers who always keep the big picture in mind.

This reminds me of a piece I wrote up on Kevin Dunbar (here) and his work investigating how scientists think. He came to the conclusion that when they use metaphors and analogies to describe their work to scientists in specialties not identical to their own, new insights and breakthroughs can occur. (Note: he takes a more nuanced approach than I’m able to use in a single, descriptive sentence.) What strikes me is that scientists often need to take a more ‘artistic and intuitive’ [my words] approach to convey information if they are to experience true breakthroughs.

My last bit is an item about more tactile robotic skin. From the news item on the Azonano website,

Peratech Limited, the leader in new materials designed for touch technology solutions, has announced that they have been commissioned by the MIT Media Lab to develop a new type of electronic ‘skin’ that enables robotic devices to detect not only that they have been touched but also where and how hard the touch was.

The key to the sensing technology is Peratech’s patented ‘QTC’ materials. QTC’s, or Quantum Tunnelling Composites, are a unique new material type which provides a measured response to force and/or touch by changing its electrical resistance – much as a dimmer light switch controls a light bulb. This enables a simple electronic circuit within the robot to determine touch. Being easily formed into unique shapes – including being ‘draped’ over an object much like a garment might, QTC’s provide a metaphor [emphasis mine] for how human skin works to detect touch.

Yes, I found another reference to metaphors although this metaphor is being used to convey information to a nontechnical audience. As for the ‘graphite whiskers’ in the title for the article which opened this posting, it is another metaphor and here, I suspect, it’s being used to describe something to other scientists who have specialties that are not identical to the researchers’ (as per Kevin Dunbar’s work).