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Better Manufacturing Method for Wound Closures (c) Wilson College of Textiles
03.01.2024

Better Manufacturing Method for Wound Closures

If you’ve ever gotten stitches or had surgery, you may have had a suture. They’re the threads used to close wounds or join tissues together for other purposes.

But did you know that there are different types of sutures which can have an effect on your experience at the doctor or surgeon’s office?

Barbed sutures, for example, can reduce the amount of time you spend on the operating table and lower the likelihood of surgical complications. That type of suture has its roots in the Triangle and is being advanced by students and faculty at the Wilson College of Textiles.

Dr. Gregory Ruff, a nationally-renowned plastic surgeon, first invented the innovative closure in 1991, just down the road in Chapel Hill, North Carolina.

“I was thinking about the fact that we sew wounds together with a loop and a knot and if you tie it too tight, it can constrict the circulation and kill the tissue in that loop,” Dr. Ruff remembers.

If you’ve ever gotten stitches or had surgery, you may have had a suture. They’re the threads used to close wounds or join tissues together for other purposes.

But did you know that there are different types of sutures which can have an effect on your experience at the doctor or surgeon’s office?

Barbed sutures, for example, can reduce the amount of time you spend on the operating table and lower the likelihood of surgical complications. That type of suture has its roots in the Triangle and is being advanced by students and faculty at the Wilson College of Textiles.

Dr. Gregory Ruff, a nationally-renowned plastic surgeon, first invented the innovative closure in 1991, just down the road in Chapel Hill, North Carolina.

“I was thinking about the fact that we sew wounds together with a loop and a knot and if you tie it too tight, it can constrict the circulation and kill the tissue in that loop,” Dr. Ruff remembers.

“I was thinking about animals, and a porcupine’s quill came to mind. And the aha moment was, ‘What if we put a quill on one side of the wound and another one on the other side of the wound, so there’s no loop: the barbs go in but they don’t come out?’”

As the name suggests, barbed sutures have small projections shooting out of them that can latch onto tissues: think about barbed wire or a fishing hook. Those “quills,” or barbs, allow the suture to self-anchor. Since no knot is needed to secure the suture, the closure is faster, and the lack of knots and constricting loops promotes healing. This also allows surgeons to schedule more surgeries.

Soon after his aha moment, Dr. Ruff started his own company, Quill Medical, to fabricate these barbed sutures. While he had the medical expertise and a solid business partner, Dr. Ruff was looking for someone who could advise him in terms of the material makeup of the suture. The Wilson College’s Biomedical Textile Research Group, under the direction of Professor Martin King, quickly proved to be the perfect partner.

Using the Wilson College’s labs, King’s graduate students conducted a number of tests on Ruff’s sutures across different types of tissues (such as skin, muscle, etc.). One of those students, Nilesh Ingle, found that the barbed sutures worked best when the angles of the barbs were tailored specifically to the type of tissue being sutured.

Years later, one of King’s current graduate students is building on that research insight.
 
Understanding challenges and innovating solutions
Nearly three decades after the barbed suture’s invention, the majority of surgeons still use conventional sutures despite the advantages documented by researchers and surgeons. Why?

Karuna Nambi Gowri, a fiber and polymer science doctoral student in King’s research group, says it comes down to two reasons. The first of these is resistance to change. Most practicing surgeons learned how to use a suture before barbed sutures became more broadly available.

The second obstacle to the use of barbed sutures is procuring them. Barbed sutures tend to be both expensive and low in supply. That’s because the current process for making them (mechanical and blade-based) is inefficient in terms of both time and resources.

That’s where Nambi Gowri’s research with the Wilson College’s Biomedical Textiles Research Group comes in. She’s developing a faster and cheaper method for making the same quality of barbed suture.

“If I fabricate using a laser, the fabrication time is pretty short compared to a mechanical barbing technique,” Nambi Gowri says.

Moving from a mechanical method to a laser method has another advantage.

“The manipulation of the barbed suture itself is easier using a laser,” she says.

In other words, using the lasers will allow Nambi Gowri to apply the custom barb geometries, or angles, suggested by prior researchers on a commercial scale. These custom geometries will allow the barbed suture to be optimized for the type of tissue it will be connecting.

In addition to the new process, Nambi Gowri is also developing a new suture.

“I’m the first one to actually study Catgut barbed sutures,” she explains.

Catgut was actually one of the earliest materials used to make sutures. The filament is made from tissue taken from an animal’s stomach – especially cattle stomachs – hence the name. While the industry had moved away from this material in favor of synthetic polymers, Nambi Gowri sees the potential for Catgut in barbed sutures because of their quick degradation rate.

“These are useful external wound closures,” she says. “Because our body contains so much collagen and Catgut is made up of 90% collagen, it’s a more suitable polymer that can be used in human tissue.”

Hands-on experience informs research
In the meantime, Nambi Gowri has gained hands-on experience to inform her research by fabricating all of the barbed sutures used in Dr. Ruff’s micro facelift surgeries.

The surgery itself is made possible because of the shape and the material composition of the sutures: poly 4-hydroxybutyrate (P4HB). This polymer is already present naturally within our bodies, so sutures made from P4HB are naturally and safely absorbed by the body over time. That means patients don’t have to schedule an appointment after surgery for the sutures to be removed.
 
P4HB also provides the perfect combination of strength and elasticity to hold up the facial tissue until the wound has healed. The barbs, on the other hand, allow for the suture to be placed and stay secure within the skin without the need for large incisions.

“That skin tightens up right away,” Dr. Ruff says of the procedure, which draws patients from across the country. “So I don’t have to remove hair, and I don’t have to put a scar at the hairline.”

“These sutures are not available commercially anywhere in the world. So, to be able to mechanically barb different size sutures in a reliable and consistent manner for use in clinical practice, requires skill, experience and knowledge of quality control,” Professor King says of Nambi Gowri’s work.

This has given Karuna a hands-on understanding of the sutures she’s hoping to improve upon.

She says her fiber and polymer science knowledge has played a key role in helping her approach all sides of her research.

“All the analytical characterization techniques that are used for characterization of sutures – like identifying mechanical properties and measuring tensile strength – is actually from my knowledge of textiles,” she says. “I’m applying my polymer chemistry knowledge  to make sure that the laser doesn’t cause the sutures to degrade, melt or experience thermal damage.”

What’s next?
As she works to patent her designs, Nambi Gowri feels confident that her dissertation will set her up for success in the research and development (R&D) field after graduation.

In the meantime, she’s already finding out about the ways her research can have a broader impact.

“Dr. Dan Duffy, DVM, a surgeon at the NC State College of Veterinary Medicine is also interested in using barbed sutures to repair torn and failed tendons on his animals, but he finds the cost of buying commercial barbed sutures prohibitively expensive. So we need to collaborate,” King says. “Karuna to the rescue!”

Source:

North Carolina State University, Sarah Stone

Firefighter Photo: 12019 at Pixabay
11.12.2023

Study tests firefighter turnout gear with, without PFAS


Transitioning away from per- and polyfluoroalkyl substances (PFAS), which offer water- and oil-repelling properties on the outer shells of firefighter turnout gear, could bring potential performance tradeoffs, according to a new study from North Carolina State University.

The study showed that turnout gear without PFAS outer shell coatings were not oil-repellent, posing a potential flammability hazard to firefighters if exposed to oil and flame, said Bryan Ormond, assistant professor of textile engineering, chemistry and science at NC State and corresponding author of a paper describing the research.

“All oil repellents can also repel water, but all water repellents don’t necessarily repel oil,” Ormond said. “Diesel fuel is really difficult to repel, as is hydraulic fluid; in our testing, PFAS-treated materials repel both. In our tests, turnout gear without PFAS repelled water but not oil or hydraulic fluid.


Transitioning away from per- and polyfluoroalkyl substances (PFAS), which offer water- and oil-repelling properties on the outer shells of firefighter turnout gear, could bring potential performance tradeoffs, according to a new study from North Carolina State University.

The study showed that turnout gear without PFAS outer shell coatings were not oil-repellent, posing a potential flammability hazard to firefighters if exposed to oil and flame, said Bryan Ormond, assistant professor of textile engineering, chemistry and science at NC State and corresponding author of a paper describing the research.

“All oil repellents can also repel water, but all water repellents don’t necessarily repel oil,” Ormond said. “Diesel fuel is really difficult to repel, as is hydraulic fluid; in our testing, PFAS-treated materials repel both. In our tests, turnout gear without PFAS repelled water but not oil or hydraulic fluid.

“Further, oils seem to spread out even more on the PFAS-free gear, potentially increasing the hazard.”

PFAS chemicals – known as forever chemicals because of their environmental persistence – are used in food packaging, cookware and cosmetics, among other uses, but have recently been implicated in higher risks of cancer, higher cholesterol levels and compromised immune systems in humans. In response, firefighters have sought alternative chemical compounds – like the hydrocarbon wax coating used in the study – on turnout gear to repel water and oils.

Besides testing the oil- and water-repelling properties of PFAS-treated and PFAS-free outer garments, the NC State researchers also compared how the outer shells aged in job-related exposures like weathering, high heat and repeated laundering, and whether the garments remained durable and withstood tears and rips.

The study showed that PFAS-treated and PFAS-free outer shells performed similarly after exposure to UV rays and various levels of heat and moisture, as well as passes through heating equipment – similar to a pizza oven – and through washing machines.

“Laundering the gear is actually very damaging to turnout gear because of the washing machine’s agitation and cleaning agents used,” Ormond said.

“We also performed chemical analyses to see what’s happening during the weathering process,” said Nur Mazumder, an NC State doctoral student in fiber and polymer science and lead author of the paper. “Are we losing the PFAS chemistries, the PFAS-free chemistries or both when we age the garments? It turns out that we lost significant amounts of both of these finishes after the aging tests.”

Both types of garments performed similarly when tested for strength against tearing the outer shell fabric. The researchers say the PFAS and PFAS-free coatings didn’t seem to affect this attribute.

Ormond said that future work will explore how much oil repellency is needed by firefighters out in the field.
“Even with PFAS treatment, you see a difference between a splash of fluid and soaked-in fluid,” Ormond said. “For all of its benefits, PFAS-treated gear, when soaked, is dangerous to firefighters. So we need to really ask ‘What do firefighters need?’ If you’re not experiencing this need for oil repellency, there’s no worry about switching to non-PFAS gear. But firefighters need to know the non-PFAS gear will absorb oil, regardless of what those oils are.”

Andrew Hall, another NC State doctoral student in fiber and polymer science and co-author on the paper, is also testing dermal absorption, or taking the aged outer shell materials and placing them on a skin surrogate for a day or two. Are outer shell chemicals absorbed in the skin surrogate after these admittedly extreme exposure durations?

“Firefighting as a job is classified as a carcinogen but it shouldn’t have to be,” Ormond said. “How do we make better gear for them? How do we come up with better finishes and strategies for them?

“These aren’t just fabrics,” Ormond said. “They are highly engineered pieces of material that aren’t easily replaced.”

The paper appears in the Journal of Industrial Textiles. Funding for the research came from the Federal Emergency Management Agency’s Assistance to Firefighters Grants Program.

Source:

North Carolina State University, Mick Kulikowski

TiHive Wins RISE® Innovation Award for their SAPMonit Technology Photo INDA
03.10.2023

TiHive Wins RISE® Innovation Award for their SAPMonit Technology

Business leaders, product developers, and technology scouts convened at the RISE® (Research, Innovation & Science for Engineered Fabrics) Conference, Sept. 26-27, Raleigh, NC for two days of valuable insights in material science, process and sustainability innovations. RISE is co-organized by INDA and The Nonwovens Institute, North Carolina State University.

Industry, academic, and government experts shared their expertise in these key areas:

Business leaders, product developers, and technology scouts convened at the RISE® (Research, Innovation & Science for Engineered Fabrics) Conference, Sept. 26-27, Raleigh, NC for two days of valuable insights in material science, process and sustainability innovations. RISE is co-organized by INDA and The Nonwovens Institute, North Carolina State University.

Industry, academic, and government experts shared their expertise in these key areas:

  • The future of nonwoven manufacturing
  • Real-world applications and advances in filter media
  • rPolymers and sustainability
  • Innovative strategies and circular solutions
  • Advancements in sustainable nonwoven applications
  • Market statistics and data trends

A highlight of RISE was a poster presentation of fundamental nonwovens research by The Nonwovens Institute’s graduate students. As an added value, The Nonwovens Institute offered RISE participants a tour of its world-class facilities located on the Centennial Campus of North Carolina State University, featuring the most extensive set of lab- and pilot-scale equipment found anywhere including all the nonwovens platform and testing technologies.

RISE® Innovation Award Winner
TiHive won the 2023 RISE Innovation Award for their SAPMonit technology. TiHive’s innovation, SAPMonit – a technology breakthrough, inspects millions of diapers weekly. SAPMonit delivers lightning-speed inline inspection of superabsorbents’ weight and distribution, optimizes resources, detects flaws, and accelerates R&D. SAPMonit utilizes advanced see-through cameras, high-speed vision algorithms, and secure cloud integration, revolutionizing industry norms. SAPMonit has great potential for sustainability, cost reduction, and enhanced customer satisfaction as it avoids hundreds of tons of plastic waste per year per machine.

The RISE Innovation Award finalists included Curt. G. Joa, Inc. for their ESC-8 – The JOA® Electronic Size Change, Fiberpartner Aps for their BicoBio Fiber, and Reifenhäuser REICOFIL GmbH & Co. KG for their Reifenhäuser Reicofil RF5 XHL.  Together, these finalists’ innovations have the potential to reduce plastic waste by millions of kgs.

DiaperRecycle won the 2022 RISE® Innovation Award for its innovative technology to recycle used diapers into absorbent and flushable cat litter. By diverting used diapers from households and institutions, and separating the plastic and fiber, DiaperRecycle strives to decrease the climate-changing emissions of diapers from landfills.

2023 INDA Lifetime Technical Achievement Award
Ed Thomas, President, Nonwoven Technology Associates, LLC, received the 2023 INDA Lifetime Technical Achievement Award for his decades of nonwoven contributions to the growth and success of the nonwoven industry.

RISE 2024 will be held October 1-2, 2024 at the James B. Hunt Jr. Library at North Carolina State University in Raleigh, NC.

More information:
INDA RISE® nonwovens
Source:

INDA

Researchers made shape-changing fibers by encapsulating a balloon-like tube in a braided textile sheath. (c) : Muh Amdadul Hoque. Researchers made shape-changing fibers by encapsulating a balloon-like tube in a braided textile sheath.
27.09.2023

Artificial Muscle Fibers Could Serve as Cell Scaffolds

In two new studies, North Carolina State University researchers designed and tested a series of textile fibers that can change shape and generate force like a muscle. In the first study, the researchers focused on the materials’ influence on the artificial muscles’ strength and contraction length. The findings could help researchers tailor the fibers for different applications.

In the second, proof-of-concept study, the researchers tested their fibers as scaffolds for live cells. Their findings suggest the fibers – known as “fiber robots” – could potentially be used to develop 3D models of living, moving systems in the human body.

In two new studies, North Carolina State University researchers designed and tested a series of textile fibers that can change shape and generate force like a muscle. In the first study, the researchers focused on the materials’ influence on the artificial muscles’ strength and contraction length. The findings could help researchers tailor the fibers for different applications.

In the second, proof-of-concept study, the researchers tested their fibers as scaffolds for live cells. Their findings suggest the fibers – known as “fiber robots” – could potentially be used to develop 3D models of living, moving systems in the human body.

“We found that our fiber robot is a very suitable scaffold for the cells, and we can alter the frequency and contraction ratio to create a more suitable environment for cells,” said Muh Amdadul Hoque, graduate student in textile engineering, chemistry and science at NC State. “These were proof-of concept studies; ultimately, our goal is to see if we can study these fibers as a scaffold for stem cells, or use them to develop artificial organs in future studies.”
 
Researchers made the shape-changing fibers by encapsulating a balloon-like tube, made of a material similar to rubber, in a braided textile sheath. Inflating the interior balloon with an air pump makes the braided sheath expand, causing it to shorten.

The researchers measured the force and contraction rates of fibers made from different materials in order to understand the relationship between material and performance. They found that stronger, larger diameter yarns generated a stronger contraction force. In addition, they found that the material used to make the balloon impacted the magnitude of the contraction and generated force.
 
“We found that we could tailor the material properties to the required performance of the device,” said Xiaomeng Fang, assistant professor of textile engineering, chemistry and science at NC State. “We also found that we can make this device small enough so we can potentially use it in fabric formation and other textile applications, including in wearables and assistive devices.”
 
In a follow-up study, researchers evaluated whether they could use the shape-changing fibers as a scaffold for fibroblasts, a cell type found in connective tissues that help support other tissues or organs.

“The idea with stretching is to mimic the dynamic nature of how your body moves,” said Jessica Gluck, assistant professor of textile engineering, chemistry and science at NC State, and a study co-author.

They studied the cells’ response to the motion of the shape-changing fibers, and to different materials used in the fibers’ construction. They found the cells were able to cover and even penetrate the fiber robot’s braiding sheath. However, they saw decreases in the cells’ metabolic activity when the fiber robot’s contraction extended beyond a certain level, compared to a device made of the same material that they kept stationary.

The researchers are interested in building on the findings to see if they could use the fibers as a 3D biological model, and to investigate whether movement would impact cell differentiation. They said their model would be an advance over other existing experimental models that have been developed to show cellular response to stretching and other motion, since they can only move in two dimensions.
 
“Typically, if you want to add stretch or strain on cells, you would put them onto a plastic dish, and stretch them in one or two directions,” Gluck said. “In this study, we were able to show that in this 3D dynamic culture, the cells can survive for up to 72 hours.

“This is particularly useful for stem cells,” Gluck added. “What we could do in the future is look at what could happen at the cellular level with mechanical stress on the cells. You could look at muscle cells and see how they’re developing, or see how the mechanical action would help differentiate the cells.”

The study, “Effect of Material Properties on Fiber-Shaped Pneumatic Actuators Performance” was published in Actuators on March 18. Emily Petersen was a co-author. The study was funded by start-up funding awarded to Fang from the Department of Textile Engineering, Chemistry and Science at NC State.

The study, “Development of a Pneumatic-Driven Fiber-Shaped Robot Scaffold for Use as a Complex 3D Dynamic Culture System” was published online in Biomimetics on April 21. In addition to Gluck, Hoque and Fang, co-authors included Nasif Mahmood, Kiran M. Ali, Eelya Sefat, Yihan Huang, Emily Petersen and Shane Harrington. The study was funded by the NC State Wilson College of Textiles, the Department of Textile Engineering, Chemistry and Science and the Wilson College of Textiles Research Opportunity Seed Fund Program.

Source:

North Carolina State University, Laura Oleniacz. Übersetzung Textination

Photo: zephylwer0, Pixabay
29.08.2023

Taming a fire: A new way with nanoscale material

High-temperature flames are used to create a wide variety of materials – but once you start a fire, it can be difficult to control how the flame interacts with the material you are trying to process. Researchers have now developed a technique that utilizes a molecule-thin protective layer to control how the flame’s heat interacts with the material – taming the fire and allowing users to finely tune the characteristics of the processed material.

“Fire is a valuable engineering tool – after all, a blast furnace is only an intense fire,” says Martin Thuo, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University. “However, once you start a fire, you often have little control over how it behaves.

High-temperature flames are used to create a wide variety of materials – but once you start a fire, it can be difficult to control how the flame interacts with the material you are trying to process. Researchers have now developed a technique that utilizes a molecule-thin protective layer to control how the flame’s heat interacts with the material – taming the fire and allowing users to finely tune the characteristics of the processed material.

“Fire is a valuable engineering tool – after all, a blast furnace is only an intense fire,” says Martin Thuo, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University. “However, once you start a fire, you often have little control over how it behaves.

“Our technique, which we call inverse thermal degradation (ITD), employs a nanoscale thin film over a targeted material. The thin film changes in response to the heat of the fire, and regulates the amount of oxygen that can access the material. That means we can control the rate at which the material heats up – which, in turn, influences the chemical reactions taking place within the material. Basically, we can fine-tune how and where the fire changes the material.”

Here’s how ITD works. You start out with your target material, such as a cellulose fiber. That fiber is then coated with a nanometer thick layer of molecules. The coated fibers are then exposed to an intense flame. The outer surface of the molecules combusts easily, raising the temperature in the immediate vicinity. But the inner surface of the molecular coating chemically changes, creating an even thinner layer of glass around the cellulose fibers. This glass limits the amount of oxygen that can access the fibers, preventing the cellulose from bursting into flames. Instead, the fibers smolder – burning slowly, from the inside out.

“Without the ITD’s protective layer, applying flame to cellulose fibers would just result in ash,” Thuo says. “With the ITD’s protective layer, you end up with carbon tubes.

“Without the ITD’s protective layer, applying flame to cellulose fibers would just result in ash,” Thuo says. “With the ITD’s protective layer, you end up with carbon tubes.

“We can engineer the protective layer in order to tune the amount of oxygen that reaches the target material. And we can engineer the target material in order to produce desirable characteristics.”

The researchers conducted proof-of-concept demonstrations with cellulose fibers to produce microscale carbon tubes.

The researchers could control the thickness of the carbon tube walls by controlling the size of the cellulose fibers they started with; by introducing various salts to the fibers (which further controls the rate of burning); and by varying the amount of oxygen that passes through the protective layer.

“We have several applications in mind already, which we will be addressing in future studies,” Thuo says. “We’re also open to working with the private sector to explore various practical uses, such as developing engineered carbon tubes for oil-water separation – which would be useful for both industrial applications and environmental remediation.”

The paper, “Spatially Directed Pyrolysis via Thermally Morphing Surface Adducts,” is published in the journal Angewandte Chemie. Co-authors are Dhanush Jamadgni and Alana Pauls, Ph.D. students at NC State; Julia Chang and Andrew Martin, postdoctoral researchers at NC State; Chuanshen Du, Paul Gregory, Rick Dorn and Aaron Rossini of Iowa State University; and E. Johan Foster at the University of British Columbia.

Source:

North Carolina State University, Matt Shipman

(c) NC State
07.08.2023

Wearable Connector Technology - Benefits to Military, Medicine and beyond

What comes to mind when you think about “wearable technology?” In 2023, likely a lot, at a time when smartwatches and rings measure heart rates, track exercise and even receive text messages. Your mind might even drift to that “ugly” light-up sweater or costume you saw last Halloween or holiday season.

At the Wilson College of Textiles, though, researchers are hard at work optimizing a truly new-age form of wearable technology that can be proven useful in a wide range of settings, from fashion and sports to augmented reality, the military and medicine.

Currently in its final stages, this grant-funded project could help protect users in critical situations, such as soldiers on the battlefield and patients in hospitals, while simultaneously pushing the boundaries of what textiles research can accomplish.

What comes to mind when you think about “wearable technology?” In 2023, likely a lot, at a time when smartwatches and rings measure heart rates, track exercise and even receive text messages. Your mind might even drift to that “ugly” light-up sweater or costume you saw last Halloween or holiday season.

At the Wilson College of Textiles, though, researchers are hard at work optimizing a truly new-age form of wearable technology that can be proven useful in a wide range of settings, from fashion and sports to augmented reality, the military and medicine.

Currently in its final stages, this grant-funded project could help protect users in critical situations, such as soldiers on the battlefield and patients in hospitals, while simultaneously pushing the boundaries of what textiles research can accomplish.

“The goals set for this research are quite novel to any other literature that exists on wearable connectors” says Shourya Dhatri Lingampally, Wilson College of Textiles graduate student and research assistant involved in the project alongside Wilson College Associate Professor Minyoung Suh.

Ongoing since the fall of 2021, Suh and Lingampally’s work focuses on textile-integrated wearable connectors, a unique, high-tech sort of “bridge” between flexible textiles and external electronic devices. At its essence, the project aims to improve these connectors’ Technology Readiness Level — a key rating used by NASA and the Department of Defense used to assess a particular technology’s maturity.

To do this, Lingampally and her colleagues’ research examines problems that have, in the past, affected the performance of wearable devices.

Sure, these advances may benefit fashion, leading to eccentric shirts, jackets, or accessories — “to light up or change its color based on the wearer’s biometric data,” Lingampally offers — the research has roots in a much deeper mission.

Potential benefits to military, medicine and beyond
The project is funded through more than $200,000 in grant money from Advanced Functional Fabrics of America (AFFOA), a United States Manufacturing Innovation Institute (MII) located in Cambridge, Massachusetts. The mission of AFFOA is to support domestic manufacturing capability to support new technical textile products, such as textile-based wearable technologies.

A key purpose of the research centers around improving the functionality of wearable monitoring devices with which soldiers are sometimes outfitted to monitor the health and safety of their troops remotely.

Similar devices allow doctors and other medical personnel to remotely monitor the health of patients even while away from the bedside.

Though such technology has existed for years, it’s too often required running wires and an overall logistically-unfriendly design. That could soon change.

“We have consolidated the electronic components into a small snap or buckle, making the circuits less obtrusive to the wearer,” Lingampally says, explaining the team’s innovations, which include 3D printing the connector prototypes using stereolithography technology.

“We are trying to optimize the design parameters in order to enhance the electrical and mechanical performance of these connectors,” she adds.

To accomplish their goals, the group collaborated with NC State Department of Electrical and Computer Engineering Assistant Research Professor James Dieffenderfer. The team routed a variety of electrical connections and interconnects like conductive thread, epoxy and solder through textile materials equipped with rigid electronic devices.

They also tested the components for compatibility with standard digital device connections like USB 2.0 and I2C.

Ultimately, Lingampally hopes their work will make wearable technology not only easier and more comfortable to use, but available at a lower price, too.

“I would like to see them scaled, to be mass manufactured, so they can be cost efficient for any industry to use,” she explains.

In a bigger-picture sense, though, her team’s work is reinforcing the far-reaching boundaries of what smart textile research can accomplish; a purpose that stretches far beyond fashion or comfort.

Pushing the boundaries of textiles research
Suh and Lingampally’s work is just the latest breakthrough research originating from the Wilson College of Textiles that’s aimed at solving critical problems in the textile industry and beyond.

“The constant advancements in technology and materials present immense potential for the textile industry to drive positive change across a range of fields from fashion to healthcare and beyond,” Lingampally, a graduate student in the M.S. Textiles program, says, noting the encouragement she feels in her program to pursue innovation and creativity in selecting and advancing her research.

Additionally, in the fiber and polymer science doctoral program, which Suh does research with, candidates focus their research on a seemingly endless array of STEM topics, ranging from forensics to medical textiles, nanotechnology and, indeed, smart wearable technology (just to name a few).

In this case, Suh says, the research lent itself to “unexpected challenges” that required intriguing adaptations “at every corner.” But, ultimately, it led to breakthroughs not previously seen in the wearable technology industry, attracting interest from other researchers outside the university, and private companies, too.

“This project was quite exploratory by nature as there hasn’t been any prior research aiming to the same objectives,” Suh says.

Meanwhile, the team has completed durability and reliability testing on its textile-integrated wearable connectors. Eventually, the group would like to increase the sample size for testing to strengthen and validate the findings. The team also hopes to evaluate new, innovative interconnective techniques, as well as other 3D printing techniques and materials as they work to further advance wearable technologies.

Source:

North Carolina State University, Sean Cudahy

A cotton knit fabric dyed blue and washed 10 times to simulate worn garments is enzymatically degraded to a slurry of fine fibers and "blue glucose" syrup that are separated by filtration - both of these separated fractions have potential recycle value. A cotton knit fabric dyed blue and washed 10 times to simulate worn garments is enzymatically degraded to a slurry of fine fibers and "blue glucose" syrup that are separated by filtration - both of these separated fractions have potential recycle value. Credit: Sonja Salmon.
11.04.2023

Researchers Separate Cotton from Polyester in Blended Fabric

In a new study, North Carolina State University researchers found they could separate blended cotton and polyester fabric using enzymes – nature’s tools for speeding chemical reactions. Ultimately, they hope their findings will lead to a more efficient way to recycle the fabric’s component materials, thereby reducing textile waste. However, they also found the process need more steps if the blended fabric was dyed or treated with chemicals that increase wrinkle resistance.

In a new study, North Carolina State University researchers found they could separate blended cotton and polyester fabric using enzymes – nature’s tools for speeding chemical reactions. Ultimately, they hope their findings will lead to a more efficient way to recycle the fabric’s component materials, thereby reducing textile waste. However, they also found the process need more steps if the blended fabric was dyed or treated with chemicals that increase wrinkle resistance.

“We can separate all of the cotton out of a cotton-polyester blend, meaning now we have clean polyester that can be recycled,” said the study’s corresponding author Sonja Salmon, associate professor of textile engineering, chemistry and science at NC State. “In a landfill, the polyester is not going to degrade, and the cotton might take several months or more to break down. Using our method, we can separate the cotton from polyester in less than 48 hours.”
 
According to the U.S. Environmental Protection Agency, consumers throw approximately 11 million tons of textile waste into U.S. landfills each year. Researchers wanted to develop a method of separating the cotton from the polyester so each component material could be recycled.

In the study, researchers used a “cocktail” of enzymes in a mildly acidic solution to chop up cellulose in cotton. Cellulose is the material that gives structure to plants’ cell walls. The idea is to chop up the cellulose so it will “fall out” out of the blended woven structure, leaving some tiny cotton fiber fragments remaining, along with glucose. Glucose is the biodegradable byproduct of degraded cellulose. Then, their process involves washing away the glucose and filtering out the cotton fiber fragments, leaving clean polyester.
 
“This is a mild process – the treatment is slightly acidic, like using vinegar,” Salmon said. “We also ran it at 50 degrees Celsius, which is like the temperature of a hot washing machine.
“It’s quite promising that we can separate the polyester to a clean level,” Salmon added. “We still have some more work to do to characterize the polyester’s properties, but we think they will be very good because the conditions are so mild. We’re just adding enzymes that ignore the polyester.”

They compared degradation of 100% cotton fabric to degradation of cotton and polyester blends, and also tested fabric that was dyed with red and blue reactive dyes and treated with durable press chemicals. In order to break down the dyed materials, the researchers had to increase the amount of time and enzymes used. For fabrics treated with durable press chemicals, they had to use a chemical pre-treatment before adding the enzymes.

“The dye that you choose has a big impact on the potential degradation of the fabric,” said the study’s lead author Jeannie Egan, a graduate student at NC State. “Also, we found the biggest obstacle so far is the wrinkle-resistant finish. The chemistry behind that creates a significant block for the enzyme to access the cellulose. Without pre-treating it, we achieved less than 10% degradation, but after, with two enzyme doses, we were able to fully degrade it, which was a really exciting result.”

Researchers said the polyester could be recycled, while the slurry of cotton fragments could be valuable as an additive for paper or useful addition to composite materials. They’re also investigating whether the glucose could be used to make biofuels.

“The slurry is made of residual cotton fragments that resist a very powerful enzymatic degradation,” Salmon said. “It has potential value as a strengthening agent. For the glucose syrup, we’re collaborating on a project to see if we can feed it into an anaerobic digester to make biofuel. We’d be taking waste and turning it into bioenergy, which would be much better than throwing it into a landfill.”

The study, “Enzymatic textile fiber separation for sustainable waste processing,” was published in Resources, Environment and Sustainability. Co-authors included Siyan Wang, Jialong Shen, Oliver Baars and Geoffrey Moxley. Funding was provided by the Environmental Research and Education Foundation, Kaneka Corporation and the Department of Textile Engineering, Chemistry and Science at NC State.

Source:

North Carolina State University, Laura Oleniacz

North Carolina State University
17.01.2023

Embroidery as Low-Cost Solution for Making Wearable Electronics

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

Embroidering power-generating yarns onto fabric allowed researchers to embed a self-powered, numerical touch-pad and movement sensors into clothing. The technique offers a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple – you can stitch our yarns directly on the fabric,” said the study’s lead author Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about the wearable devices. You can integrate the power-generating yarns after the clothing item has been made.”

In the study published in Nano Energy, researchers tested multiple designs for power-generating yarns. To make them durable enough to withstand the tension and bending of the embroidery stitching process, they ultimately used five commercially available copper wires, which had a thin polyurethane coating, together. Then, they stitched them onto cotton fabric with another material called PTFE.

“This is a low-cost method for making wearable electronics using commercially available products,” Yin said. “The electrical properties of our prototypes were comparable to other designs that relied on the same power generation mechanism.”

The researchers relied on a method of generating electricity called the “triboelectric effect,” which involves harnessing electrons exchanged by two different materials, like static electricity. They found the PTFE fabric had the best performance in terms of voltage and current when in contact with the polyurethane-coated copper wires, as compared to other types of fabric that they tested, including cotton and silk. They also tested coating the embroidery samples in plasma to increase the effect.

“In our design, you have two layers – one is your conductive, polyurethane-coated copper wires, and the other is PTFE, and they have a gap between them,” Yin said. “When the two non-conductive materials come into contact with each other, one material will lose some electrons, and some will get some electrons. When you link them together, there will be a current.”
Researchers tested their yarns as motion sensors by embroidering them with the PTFE fabric on denim. They placed the embroidery patches on the palm, under the arm, at the elbow and at the knee to track electrical signals generated as a person moves. They also attached fabric with their embroidery on the insole of a shoe to test its use as a pedometer, finding their electrical signals varied depending on whether the person was walking, running or jumping.

Lastly, they tested their yarns in a textile-based numeric keypad on the arm, which they made by embroidering numbers on a piece of cotton fabric, and attaching them to a piece of PTFE fabric. Depending on the number that the person pushed on the keypad, they saw different electrical signals generated for each number.

“You can embroider our yarns onto clothes, and when you move, it generates an electrical signal, and those signals can be used as a sensor,” Yin said. “When we put the embroidery in a shoe, if you are running, it generates a higher voltage than if you were just walking. When we stitched numbers onto fabric, and press them, it generates a different voltage for each number. It could be used as an interface.”

Since textile products will inevitably be washed, they tested the durability of their embroidery design in a series of washing and rubbing tests. After hand washing and rinsing the embroidery with detergent, and drying it in an oven, they found no difference or a slight increase in voltage. For the prototype coated in plasma, they found weakened but still superior performance compared with the original sample. After an abrasion test, they found that there was no significant change in electrical output performance of their designs after 10,000 rubbing cycles.

In future work, they plan to integrate their sensors with other devices to add more functions.
“The next step is to integrate these sensors into a wearable system,” Yin said.

The study, “Flexible, durable and washable triboelectric yarn and embroidery for self-powered sensing and human-machine interaction,” was published online in Nano Energy. Co-authors included Yu Chen, Erdong Chen, Zihao Wang, Yali Ling, Rosie Fisher, Mengjiao Li, Jacob Hart, Weilei Mu, Wei Gao, Xiaoming Tao and Bao Yang. Funding was provided by North Carolina State University through the NC State Faculty Research & Professional Development Fund and the NC State Summer REU program.

 

Source:

North Carolina State University, Rong Yin, Laura Oleniacz