Chemistry Reference
In-Depth Information
fibres may simply be too inflexible to be incorporated into machine-sewable
yarns. However, it is important to remember that individual fibres are part
of an overall yarn geometry. Experiments with stainless-steel yarns have
shown that both yarn geometry and the percentage of conductor incorpo-
rated into a yarn also play a significant role in a yarn's flexibility, and there-
fore its sewability.
8.4.6
Electrotextile applications
For the past 20 years, the textile industry has provided simple electrotex-
tile products. Several novel uses of electrotextiles have been developed for
laboratory testing, while others have been utilised in products on the com-
mercial market, as well as in items used in space science
69,70
.The ability to
integrate electrical functionality into textile garments is becoming increas-
ingly desirable for consumer devices, military applications and for compa-
nies with large distributed workforces. This technology has the potential to
facilitate the transfer of information and increase efficiency in many areas.
Nevertheless, these products should be electrically conductive, but must
also exhibit superior flexibility, enhanced wearability, and the ability to
withstand multiple washing environments. The electrotextiles should be
tested and evaluated accordingly
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.
Clothes are worn for long periods and next to the skin and are therefore
convenient hosts for physiological monitoring of a person. Integration of
sensors onto clothes would enable comfortable monitoring. Conductive and
pressure-sensitive textiles have been incorporated in the advanced devel-
opment of space suits (I-Suit), as switch controls for lights and as signal-
transmission cables. Conductive fibres have been used in several stitched
applications for electrostatic charge dissipation, including large pharma-
ceutical containment enclosures where fine powders are being captured for
transfer between manufacturing facilities, as well as impact-attenuation
airbags used in landing spacecraft on the surface of Mars. In both cases,
conductive threads are uniquely located in seams and panel locations
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.
Electrically conductive and semi-conductive fabrics have been used in
applications such as electromagnetic interference and microwave
attenuation.
Electromagnetic interface shielding is the most common application.
Conductive fibres braided into a shield or sock offer superior performance
against electromagnetic interference,
and they present the following
advantages:
•
More uniform coverage
: the large number of very fine fibres, together
with the tendency of yarn bundles to flatten and spread, makes it easy
to obtain high coverage.
