The Next Generation in Thermal Regulating Fabrics
Sagar Doshi and Erik Thorste test an elbow sleeve with one of their novel sensors. Photo courtesy of the Univ of Delaware
University of Virginia (USA), in collaboration with Penn State, the University of Maryland and the National Institute of Standards and Technology, have invented a “switching effect” for thermal conductivity and mechanical properties that can be incorporated into textiles and garments.
Using heat transport principles combined with a biopolymer inspired by squid ring teeth, the team studied a material that can dynamically regulate its thermal properties - switching back and forth between insulating and cooling - based on the amount of water that is present.
The invention has the ability to regulate temperature and heat flow on demand, including the “smart” fabrics.
“This material has the potential to revolutionize active wear by offering fabric that can dynamically respond to body heat and regulate temperature. For example, the biopolymer has a low thermal conductivity while dry, essentially storing body heat and keeping the athlete (and his or her muscles!) warm while not active.
“As soon as the wearer begins to sweat, the material could become hydrated and instantly increase its thermal conductivity, allowing this body heat to escape through the material and cool the athlete down. When the person is done training and the sweat has evaporated, the material could go back to an insulative state and keep the wearer warm again” said John Tomko.
The garments made using this technology would be a step above what is available on the market today because of the materials’ extremely wide range of technical capabilities. For example, polar fleece generally requires different weights to accommodate different combinations of temperatures and activity levels. The new material could accommodate the whole gamut of athletic scenarios within one garment.
Seismic Unveils Powered Clothing
Seismic's lumbar support. Photo courtesy of Seismic
Seismic’s Powered Clothing fuses discreet robotics with textiles to create products that look and feel like apparel, but function more like an extension of the human body - an extra set of muscles people can put on every day.
Seismic suits support the body’s core by providing up to 30 watts of power to each hip and the lower back to support sitting, standing, lifting, carrying, and a range of other activities. Seismic will enter the consumer market with a limited release in 2019. The company plans to focus on the activewear market.
Novel Sensors For Smarter Textiles
Cycles of thermal conductivity when material is wet and then dry. Illustration courtesy of Penn State University.
A team of engineers at the University of Delaware (USA) is developing next-generation smart textiles by creating flexible carbon nanotube composite coatings on a wide range of fibres, including cotton, nylon and wool.
Fabric coated with the sensing technology could be used in ‘smart garments’ where the sensors are slipped into the soles of shoes or stitched into clothing for detecting human motion.
Carbon nanotubes give this light, flexible, breathable fabric coating impressive sensing capability. When the material is squeezed, large electrical changes in the fabric are easily measured. “As a sensor, it’s very sensitive to forces ranging from touch to tons,” said Erik Thostenson, an associate professor.
Nerve-like electrically conductive nanocomposite coatings are created on the fibers. “The films act much like a dye that adds electrical sensing functionality,” said Mr. Thostenson. “The process is industrially scalable for future applications.”
Existing techniques, such as plating fibers with metal or knitting fibre and metal strands together, can decrease the comfort and durability of fabrics, said Mr. Thostenson. The nanocomposite coating his group developed is said to be flexible and has been tested on a range of natural and synthetic fibers, including Kevlar, wool, nylon, spandex and polyester.
The coatings are just 250 to 750 nanometres thick - about 0.25 to 0.75 percent as thick as a piece of paper - and would only add about a gram of weight to a typical shoe or garment.
Tests are now being done to see how these sensors, when embedded in footwear, compare to biomechanical lab techniques such as instrumented treadmills and motion capture. The low-cost sensor is thin and flexible so the possibility exists to create custom footwear and other garments with integrated electronics to store data during people’s day-to-day lives. This data could be analysed later by researchers or therapists to assess performance and ultimately bring down the cost of healthcare.