An introduction to smart textiles

Citation

Stylios, G.K. (2004), "An introduction to smart textiles", International Journal of Clothing Science and Technology, Vol. 16 No. 5. https://doi.org/10.1108/ijcst.2004.05816eaa.001

An introduction to smart textiles

An introduction to smart textiles

The living world is said to be smart because it responds to changes of the environment that it occupies. Therefore, response to stimuli is a basic process of living beings. Based on the lessons from nature, scientists have been designing materials that respond to external stimuli such as temperature, pH, light, electric field, chemicals, etc. These responses are manifested as changes in one or more of the following: shape, surface characteristics, solubility, formation of an intricate molecular self-assembly, a solvent-to-gel transition and so on. Such structures are called “smart” and such materials referred to as “smart materials” or “Intelligent Materials” and have evolved over the past decades with increasing pace during the 1990s and particularly over the last few years.

Textiles are having an important role to play in all this as smart textiles are made up of materials as defined above, or with built-in components (e.g. sensors) that will enable data collection, response, feed back, etc.

smart materials can be divided into two groups. One group comprises the “classical” active materials as viewed by the academic community and is characterized by the type of response that these materials generate. Upon application of a stimulus the materials respond with a change in shape and/or in length of the material. Thus, input is always transformed into strain, which can be used to introduce motion or dynamics into a system. smart Polymers responsive to solvent composition, pH and temperature are being developed for potential applications like chemical valves, shape memory, as well as biomedical applications including artificial organs and drug delivery systems. The second group consists of materials that respond to stimuli with a change in a key material property, for example, electrical conductivity or viscosity.

Whichever be the distinction, however, it is reasonable to distinguish smart materials from advanced materials, as those that have multifunctionality or/and those that can have interactivity as in a sensor, actuator application.

The application possibilities of smart textiles are only limited by human imagination. Some of the end uses of smart textiles are outlined below.

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  Smart materials with the ability to sense and react to external conditions (temperature and humidity), communications, light emission and shielding the wearer from radiation.

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  Garments that sense temperature and respond by generating heat or contracting to change their warmth or moisture management characteristics.

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  Electronic fabrics that protect against the hazards posed by low-level electromagnetic radiation.

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  Garments that are softer, lighter, thinner and more permeable to vapour than conventional products, therefore providing better protection.

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  Body suits that monitor human physiological state and communicate to a central system. RIFleX at Heriot-Watt University are developing a smart vest for the rehabilitation of patients (1).

Electrically conductive polymer have attracted a substantial amount of attention since they were accidentally discovered two decades ago and the race is on to invent new conductive plastics. Conductive polymers are much more electrically conductive than standard polymers, but much less than metals such as copper. In practice, the conductivity of these materials is characterised by low-charge carrier mobility – a measure of how easily electric charge moves.

The key to smart textiles is inherently conductive polymers. Inherently conductive polymers (ICP) have a unique ability to conduct electricity. Their conductivity can be varied in the same fashion as a semi-conductor material. They are already used in non-textile applications such as flat-panel displays, photovoltaic cells and electro-chromic windows, and conductive and anti-static coatings.

The smart fabric and interactive textiles market totals $303 million today, and growth estimates vary significantly by market segment over the next 10 years. The smart fabric and interactive textile component include sensors (physiological status monitoring, cognitive status monitoring, movement/location), electronics (flexible and embedded processors/monitors/transmitters), textiles (conductive fibres, body armour, artificial muscles, bio-chemical hazard protection), energy (micro fuel cells, photo-voltaics, energy harvesting), software/database (embedded analytical software, databases with soldier physiological data). One of the predominant markets today for smart fabric and interactive textiles enabled products is the military, which accounted for close to 10 percent of annual consumption in 2003. Venture Development Corporation (US) recently completed a comprehensive market analysis of the current and emerging markets for smart fabrics and interactive textiles. The market for the above is expected to reach $520 million in 2008.

The smart fabrics and interactive textiles technologies that allow the military to communicate, respond to emergencies, and achieve informational advantage and situational awareness also have industrial and commercial applications. The applications will have impacts within the following markets: health care, emergency response, transportation safety, commercial electronics, supply chain management, sports physiology, mobile business marketing, and remote industrial structural-health diagnostics.

Figure 1

At present, the efforts of technology-push far outweigh the market demand. Markets are inherently competitive, but in the case of the smart fabric and interactive textiles market, the lack of information exchanged among peers is evident. Despite this barrier to growth, the smart fabrics and interactive textiles market continues to gain importance in a number of market segments, which exhibit higher levels of knowledge, communication and cooperation.

In an attempt to promote this area into smart clothing, the wearable electronics & smart Textiles (WEST) Interest Group (www.smartextiles.info) has set-up a competition, as shown in Figure 1.

George K. Stylios