The global e-textiles
market is promising and e-textile products are being explored in numerous
exciting areas, from thermal radiation control, body parameter measurement to
disease prevention, and many more. Leading industry players and researchers are
utilizing the many ways that fabrics can exploit electronics, as demonstrated
by a range of projects and partnerships.
The next revolution in
the industry involves the combination of electronics and textiles to form
"smart" textile products. The e-textiles market is expected to be
worth over US$1.4 billion by 2030, according to a recent report by IDTechEx
Research.
The snapshot of the
e-textile application readiness levels shows a robust pipeline. Applications such
as elite sports biometric (chest straps or apparel), heated clothing,
illuminated apparel, high-fashion e-textile apparel, carpet pressure sensors
and similar extend from the early commercial sales to full market penetration.
There are also many applications at early development phases, rendering the
pipeline deep and robust.
Despite all these,
there are many challenges. The supply chain is immature, although efficiency is
improving with co-located manufacturing. Challenges around reliability,
cross-compatibility & standards, equipment suitability, materials
availability and overheads costs have previously been prohibitive to commercial
development of many different product types.
However, thanks to
significant investments and partnerships, some of these barriers are being
lowered, with more players able to make more advanced e-textile products as
less prohibitive prices. These developments improve the chances that emerging
e-textile products have against incumbent options in each of the markets they target,
and a range of formulations now exist to address varying needs.
Wireless charging,
washable garments with printed circuits
In May 2020, Liquid X,
a manufacturer of functional metallic inks with prototype-to-production design
and manufacturing capabilities, and Powercast Corporation, a supplier in
radio-frequency (RF)-based long-range over-the-air wireless power technology,
have announced a printed electronics venture to enable garment manufacturers to
easily integrate wireless power functionality into durable, flexible, high
performance and washable e-textiles.
Utilizing Liquid X’s
proprietary, particle-free ink technology, manufacturers can print circuitry
directly onto a garment, add Powercast’s wireless power technology and a
battery, and seal this all into the garment during the manufacturing process.
The two companies’ goal
is to enable cost-effective manufacturing of durable e-textiles, with
battery-powered features such as health and wellness, movement monitoring, or
LED-based illumination embedded directly into garments, that consumers can
conveniently recharge over the air, and wash, without having to remove a
battery pack.
Today’s smart garments
often snap electronics onto the garment along with battery packs that users
must detach before washing. With the combined technologies of Liquid X and
Powercast, now manufacturers can integrate the electronics directly into the
garment.
First, circuitry is
printed on the fabric using Liquid X’s proprietary ink, including Powercast’s
RF wireless receiving antenna. Through additive manufacturing techniques,
Liquid X’s particle-free ink is deposited directly onto the fabric, conformally
coating the fibers of the fabric to create highly conductive traces, enabling
cost-effective, durable solutions for textile-based products while maintaining
the integrity of the base fabric material.
Next, Powercast’s
Powerharvester RF wireless power receiver chip, a battery, and other components
are mounted onto the printed traces. Finally, an encapsulant provides a high
strength waterproof bond to seal in all of the electronics.
To recharge the
battery, consumers simply place a Powercast RF transmitter in the closet or
drawer where they store their smart wearable. It transmits RF energy over the
air to the RF receiver embedded in the wearable, which then converts it to
direct current (DC) to charge the battery.
The two
Pennsylvania-based companies showcased at CES in January 2020 a wirelessly
rechargeable smart athletic shirt prototype that illuminates using printed
electronics, embedded power harvesting technology, and LEDs powered over the
air up to 10 feet away from the wireless transmitter.
3D-printed functional
textiles powered by novel polymer nanocomposites
Researchers at the
University of Borås, Sweden, have developed a new method for printing on
textiles which cuts short the resource intensive production process. What is
currently printed with screen or inkjet technology can now be done by printing
directly on textiles with a 3D printer. This is important in producing smart
and functional textiles.
Doctoral student Razieh
Hashemi Sanatgar has in her research project developed a new polymeric material
with electrically conductive properties used as a feeding material in the 3D
printer.
It is a nanocomposite,
a mixture of a polymer into which she mixed electrically conductive
nanofillers, including carbon nanotubes and carbon black. A systematic study of
how different mixtures of these nanocomposites attach to the textile and what
properties are achieved has been done.
The conventional
printing processes, such as screen or inkjet technology, require large amounts
of energy, water, and chemicals. The method that has now been developed opens
up great flexibility in the production process.
The goal of the
research is to develop an integrated and tailor-made production process for
smart and functional textiles that simultaneously uses less water, energy,
chemicals and makes less waste and thus leaves as little an imprint on the
environment as possible, while at the same time being of benefit from a
production point of view, as the method is both cost and resource efficient,
according to Sanatgar.
Another benefit is that
it is possible to get customized production with printing the nanocomposite
directly on the textile material on the exact places needed.
One challenge in the
project was to achieve and maintain the desired properties of electrically
conductive 3D printer filaments evenly after the filament has passed through
the 3D printer.
In the project, the
scientists have succeeded in optimizing the properties of the nanocomposite
before and after 3D printing, which is important to be able to control the
properties and their changes after printing.
Another challenge was
how well the polymers and nanocomposite adhere to different textile materials.
The results from this part of the project fill an important gap in the research
field. As 3D printing on textiles is a novel technology, the adhesion of
polymers and nanocomposites on textiles has not been thoroughly explored.
What the scientists
have now done is a systematic study where they have investigated the effect of
different printing process parameters on the adhesion of polymers and
nanocomposites on textiles.
The new process can be
used in the production of smart bandages, VR gloves, garments with sensor and
heat properties, rescue equipment, sports garments that sense body temperature,
medical equipment, the automotive, aerospace and space industry, etc. -
situations which need control of exactly where the conductive material should
be placed on the textile material and how the conductive property should
function.
Graphene textiles
developed for heat adaptive clothing
Thanks to the thermal
properties and flexibility of graphene, scientists at the University of
Manchester have created smart adaptive clothing which can lower the body
temperature in hot climates in June 2020.
They have created a
prototype garment to show dynamic thermal radiation control in clothing.
Graphene layers were used to control thermal radiation from textile.
The development also
opens the door to new applications such as, interactive infrared displays and
covert infrared communication on textiles.
The human body radiates
energy in the form of electromagnetic waves in the infrared spectrum, known as
blackbody radiation. In a hot climate it is desirable to make use of the full
extent of the infrared radiation to lower the body temperature which can be
achieved by using infrared-transparent textiles.
As for the opposite
case, infrared-blocking covers are ideal to minimize the energy loss from the
body. Emergency blankets are a common example used to deal with treating
extreme cases of body temperature fluctuation.
The collaborative team
of scientists demonstrated the dynamic transition between two opposite states
by electrically tuning the infrared emissivity (the ability to radiate energy)
of graphene layers integrated onto textiles.
One-atom thick graphene
was first isolated and explored in 2004 at the University of Manchester. Its
potential uses are vast and research has already led to leaps forward in
commercial products including batteries, mobile phones, sporting goods and
automotive.
The new research
published in journal Nano Letters, demonstrates that the smart optical textile
technology can change its thermal visibility. The technology uses graphene
layers to control thermal radiation from textile surfaces.
Professor Coskun
Kocabas, who led the research, pointed out that the ability to control the
thermal radiation is a key necessity for several critical applications such as
temperature management of the body in excessive temperature climates.
Thermal blankets are a
common example used for this purpose. However, maintaining these
functionalities as the surroundings heats up or cools down has been an
outstanding challenge.
The successful
demonstration of the modulation of optical properties on different forms of
textile can leverage the ubiquitous use of fibrous architectures and enable new
technologies operating in the infrared and other regions of the electromagnetic
spectrum for applications including textile displays, communication, adaptive
space suits, and fashion.
This study built on the
same group’s previous research using graphene to create thermal camouflage
which was able to fool infrared cameras. The new research can also be
integrated into existing mass-manufacture textile materials such as cotton.
To demonstrate, the
team developed a prototype product within a t-shirt allowing the wearer to project
coded messages invisible to the naked eye but readable by infrared cameras.
Professor Coskun
Kocabas added that the next step for this area of research is to address the
need for dynamic thermal management of earth-orbiting satellites. Satellites in
orbit experience excesses of temperature, when they face the sun and they
freeze in the earth’s shadow.
The technology could
enable dynamic thermal management of satellites by controlling the thermal
radiation and regulate the satellite temperature on demand.
Electronic fibers with
transmission lines to measure body parameters
At the Swiss Federal
Institute of Technology Lausanne (EPFL), researchers have developed electronic
fibers which can be embedded in textiles to collect information about body
parameters.
The fibers help measure
subtle and complex fabrics deformations, and through that information about
one’s body. The technology uses transmission line theory and can have several
applications, such as in health care and robotics.
The research has been
carried out by Professor Fabien Sorin and doctoral assistant Andreas Leber, at
the Laboratory of Photonic Materials and Fiber Devices (FIMAP) in EPFL's School
of Engineering. The technology can be used to detect body's movements - and
many other factors.
Imagine clothing or
hospital bed sheets capable of monitoring wearer’s breathing and other vital
movements, or AI-powered textiles that allow robots to interact more safely and
intuitively with humans - the soft transmission lines that have been developed
open the door to all of these, according to Leber.
The researchers
invented a single sensor that can detect different kinds of fabric deformation
like stretching, pressure and torque at the same time. As introduced, finding a
method for calculating all that was the biggest challenge, because it is
difficult for sensors to measure several movements simultaneously.
Leber added that
conventional sensors have several drawbacks. First, they are fragile and break
easily. Second, a lot of them are needed to cover a large area, which
eliminates many of the advantages of fabrics. And third, each type of
conventional sensor can detect only one kind of deformation.
But by incorporating
concepts from reflectometry, Sorin and Leber were able to create flexible fiber-shaped
sensors that open up new doors for smart textiles. According to Leber, the
technology works similar to a radar, but it sends out electrical impulses
instead of electromagnetic waves.
The fiber sensors
operate like transmission lines for high-frequency communication. The system
measures the time between when a signal is sent out and when it's received, and
uses that to determine the exact location, type and intensity of deformation.
This kind of detection
technology has never before been used in applications requiring high mechanical
flexibility and powerful electronic performance, which are two key features for
distortion identification.
Creating the fibers is
a complex task involving liquid metal, which serves as the conductor, and an
optical fiber fabrication process. The structure is just a few micrometers
thick and has to be perfect, otherwise it will not work.
With these fibers, the
entire surface of a fabric becomes one large sensor. The trick was to create
transmission lines made entirely of flexible materials, using a simple method
that can be scaled up easily.
The team's research
drew on a variety of disciplines including electrical engineering, mechanical
engineering, materials science and process engineering. The next step will be
to make the technology more portable by shrinking the electronic component.
Smart socks embedded
with micro-sensors for diabetes patients
Siren, a San
Francisco-based health technology company, has launched its first Neurofabric
–powered product, the Siren Diabetic Sock and Foot Monitoring System.
Neurofabric is a kind
of textile with micro-sensors embedded directly into the fabric, making its
sensors completely seamless and virtually invisible to the user.
Siren Diabetic Socks
continuously monitor foot temperature so people can detect signs of
inflammation, the precursor to diabetic foot ulcers. The onset of diabetic foot
ulcers represents a dangerous condition that, when left unchecked, can lead to
serious complications, including amputation.
Monitoring foot
temperature is clinically proven to be the most effective way of catching foot
injuries, and is up to 87% more effective at preventing diabetic foot ulcers
than standard diabetic foot care.
Current solutions for
diabetic foot monitoring rely on non-continuous and manual measurement. People
who want to monitor foot temperature have to go to the doctor and get six spots
on each foot manually measured for temperature, a time-consuming and
inefficient process.
Siren's solution
enables real-time detection and early intervention, which can prevent the
serious complications that result in over 100,000 lower limb amputations every
year and cost the US healthcare system over US$43 billion annually.
For people with
diabetic neuropathy, Siren’s socks look and feel just like a regular pair of
socks and blend seamlessly into their daily lives. Comfortable and discreet,
they provide continuous, clinical-grade temperature monitoring and health
tracking over time. All they have to do is put on their socks like they would
any other day.
Should signs of
inflammation be detected, the patient and the doctor will receive notifications
via the Siren companion app and/or text message.
Siren’s Foot Monitoring
System includes a variety of patented technologies, enabling the standard
manufacturing of integrated sensors, and simultaneous pairing of multiple
devices, both of which were previously unsolved.