Smart/interactive textiles (SMITs) are a new type of textile technology. Conductive polymers are playing an important role as conductive fibers in the development of these SMITs for a broad range of applications. In the future, along with protecting the wearer, cloth or fabrics will also have intelligent built-in features, such as multifunctional sensors or computing devices. Still in its nascent stage, electro textiles are projected to have a broad impact on the market for protective clothing, medical textiles and other applications foreseen in military, sports, medical, industrial as well as consumer products.
SMITs are able to sense electrical, thermal, chemical, magnetic or other stimuli from the environment and adapt or respond to them, using functionalities integrated into the textile structure. US military has been the leader in developing SMIT technologies and applications for such areas as body armor, artificial muscles, biochemical hazard protection, physiological status monitoring, location and embedded communications and computing. Several of these technologies have potential in civilian and commercial applications.
There are several different methods for obtaining electro-conductive fibers.
One method is synthesis of conductive fibers similar to synthesis of conductive polymers. Despite the good conductivity of these fibers, they are not commonly used as conductive fibers in textile applications because their limited flexibility restricts application possibilities.
Another method is blending common nonconductive fibers with conductive polymer fibers. The advantage of this method is that the conductive yarns have the same mechanical properties as yarns fabricated from pure non-conductive fibers. Conductive polyaniline and traditional nylon or polyester fibers may be used in the production of mixed electro and nonconductive fibers.
A third method is the synthesis of fibers from polymers with a conductive carbon molecule inclusion. However this method also limits the mechanical properties of the fibers. Another method is metallization of fibers.
Originally developed by researchers at the Georgia Institute of Technology and funded by DARPA (R&D arm of the US Department of Defense), the SmartShirt is a T-shirt-like garment that looks like and feels like soft ribbed cotton knit. But the cotton and spandex cloth is interwoven with patented conductive fibers that can receive and transmit data from embedded sensors to a special receiver the size of a credit card. Heart rate, respiration and body temperature are calibrated and relayed in real time for analysis. The receiver stores the information and can transmit it for playback to a cell phone, home personal computer or a wrist-mounted monitor. Textile engineering firm Sensatex, Inc’s 'SmartShirt' technology integrates advances in textile engineering and wearable computing with wireless data transfer to permit the collection, transmission and analysis of diverse biometric data. It is a wearable physiological information management platform with the potential to have a deep impact on a diverse number of market segments requiring information and management of information generated from the human body.
SmartShirt has enormous potential for applications in fields such as telemedicine, monitoring of patients in post-operative recovery, the prevention of SIDS (sudden infant death syndrome), and monitoring of astronauts, athletes, law enforcement personnel and combat soldiers. The garment can be configured in many ways and attached to almost any sensor including global positioning device.
A totally new area is applying conductive polymers to photovoltaic fibers in the development of textile based solar cells. Konarka Technologies Inc., an innovator in developing and commercializing power plastics that convert light to energy, has already demonstrated it can produce a working photovoltaic fiber. The company is collaborating in a long term alliance with a Swiss company to develop photovoltaic fabric in which solar power generating properties are woven into the fabric rather than applied to the fabric surface.
The market for smart fabrics and interactive textiles (SFITs) is likely to exceed USUS$640 mln by the end of 2008 as per a report by Research and Markets. This figure is well in excess of the figure of USUS$485 mln predicted in 2005. Moreover, the compound annual growth rate (CAGR) of 18% earlier forecast for 2004-08 has become as high as 27%.
The bulk of turnover in SFITs is generated in the production of intermediate components, or SFIT modules—a sector involved in combining base electronic components into a textile substrate. However, this sector is growing by a relatively slow 19% pa whereas finished SFIT-based textiles are growing by 76% pa.
The biggest single end use for SFITs continues to be heated automotive seating. But other applications are expected to catch up and overtake it, particularly textiles for physiological sensing. Demand for SFITs for military use also continues to be strong.
One of the most important technical developments in SFITs has been the replacement of metallic fibres with conductive polymers—such as polypyrrole and polyaniline. In addition, there have been important developments in fibres coated with conductive metals. A further area of major promise is the use of nanotechnology, including carbon nanotubes—provided concerns over potential health hazards can be resolved.
The SFIT industry is characterised by the presence of a large number of relatively small companies. This is a consequence of the diversity of technical expertise involved and the wide variety of developments which have emerged. In this business environment, smaller enterprises are able to occupy profitable technological niches. Larger companies, by contrast, have been reluctant to enter the SFIT market. The industry is also characterised by strategic alliances and partnerships—despite low levels of competition. These have been seen as solutions to problems arising from limited production capacities and high costs of research and marketing.
For the future, a number of issues will need to be addressed as the industry develops. One is the lack of industry standards. Another is the need for more professional marketing. Of particular importance is the need to bring down the cost of manufacture—and hence selling prices.
According to BCC Research :
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The U.S. market for smart textiles was worth an estimated US$70.9 mln in 2006. This figure is expected to reach US$78.6 mln in 2007 and US$391.7 mln in 2012, at a CAGR of 37.9% between 2007 and 2012 |
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Consumer products accounted for the bulk (98%) of U.S. smart textiles sales in 2006. However, the projected rapid growth of military, biomedical, and vehicle safety and comfort applications for smart textiles is expected to have a major impact on both the size and structure of the market. |
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Sales of conductive fabric products are expected to more than double each year between 2007 and 2012. |
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Smart textiles are able to sense electrical, thermal, chemical, magnetic, or other stimuli from the environment and adapt or respond to them, using functionalities integrated into the textile structure. They do not have a fixed set of characteristics, but are an active element that works with its own control and response mechanism.
The U.S. military historically has been the leader in developing smart textile technologies and applications in such areas as body armor, artificial muscles, biochemical hazard protection, physiological status monitoring, location, and embedded communications and computing. Many of these same technologies also have potential civilian and commercial applications. Indeed, the commercial sector has been ahead of the military in commercializing smart textile technologies.
According to Venture Development Corporation (VDC):
Interactive textiles or so-called smart fabric products will be reaching the market for healthcare/medical, public safety, military, and sporting applications later this year. These products will be designed to monitor the wearer's physical well being and vital signs such as heart rate, temperature, and caloric consumption, among many others. VDC forecasts the fastest growth for interactive textiles demand in market segments such as healthcare/medical, consumer-sports and outdoor activities, and the military, among others. Users in these markets are expected to embrace the true Wearability and comfort and bio-monitoring functionality provided by these products.
The emergence of interactive textile or "smart fabric" products will also be driven by technological improvements and increasing reliance on MEMs based integrated sensors. Development of flexible displays comprised of OLED or LEP technologies will be integrated into clothing solutions, providing the ability to view information in real-time via wireless communications.
There are many companies (some of the leaders in this development include: Sensatex, DuPont, ADA, Foster-Miller, Santa Fe Science and Technology, SOFTswitch, and International Fashion Machines, among others) developing interactive textile products for usage in a wide range of applications.
The European market for smart fabrics and interactive textiles (SFIT) represents about €300 mln in 2008 and is growing at a yearly rate of about 20%. As per the SFIT team, there are basically two kinds of smart clothes.
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The smart clothes with sensors or devices in pocket or in fabric such as microcomputers, flexible TV screens, micro cellular phone, solar cells, energy recovery systems and flexible keyboard. These devices are used mainly for communication, displaying colors, pictures, indications of mood, messages. Other devices or sensors, e.g. GPS devices, fall detectors, data loggers, accelerometer and activity detectors, can be placed in special pockets or attached in the garment. |
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The smart clothes with sensors close to or in contact with the skin, which are more used for body sensing and monitoring. The sensors are enclosed in the layers of fabric, or it is the fabric itself which is used as sensors. Such sensors can be piezo-resistive yarns, optic fibers, and colored multi layers. |
European researchers have developed a smart fabric that can monitor muscular overload and help prevent repetitive strain injury or RSI. But that is just the beginning. The team is also exploring a pregnancy belt to monitor baby’s heartbeat, clothing to help coach hockey, and shirts that monitor muscle fatigue during training. Smart fabrics promise to revolutionise clothing by incorporating sensors into cloth for health, lifestyle and business applications. In the long term, they could consist of circuits and sensors that provide all of the typical electronics we carry around today, like mobile phones and PDAs. Current, first-generation applications are far more modest, and pioneering medical smart fabrics are used to monitor vital signs like heart rate and temperature. But two crucial hurdles – unobtrusiveness and reliability – impede widespread adoption of such clever clothes. A European research team has developed groundbreaking medical-sensing smart fabrics, and its work could lead to pregnancy monitoring belts, sports clothing that provides training tips, a wearable physical game controller, and a vest that helps to prevent repetitive strain injury. |
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