Textiles and textile products - Smart textiles - Definitions, categorisation, applications and standardization needs

This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a categorisation of different types of smart textiles. It describes briefly the current stage of development of these products and their application potential and gives indications on preferential standardization needs.

Textilien und textile Produkte - Intelligente Textilien - Definitionen, Klassifizierung, Anwendungen und Normungsbedarf

Der vorliegende Technische Bericht enthält Begriffe aus dem Bereich der „intelligenten“ Textilien und textilen Erzeugnisse, sowie eine Kategorisierung verschiedener Typen von intelligenten Textilien. In Kurzform werden der aktuelle Entwicklungsstand dieser Erzeugnisse und deren Anwendungsmöglichkeit beschrieben, und es werden Angaben zu vorrangigen Normungsergebnissen gemacht.

Textiles et produits textiles - Textiles intelligents - Définitions, catégorisation, applications et besoins de normalisation

Le présent Rapport technique fournit des définitions dans le domaine des textiles et produits textiles « intelligents », ainsi qu’une catégorisation des différents types de textiles intelligents. Il décrit brièvement l’état actuel de développement de ces produits et leur application potentielle et fournit des indications sur les besoins de normalisation préférentiels.

Tekstilije - Inteligentne tekstilije - Definicije, kategorizacija, uporaba in standardizacijske potrebe

To tehnično poročilo vsebuje definicije na področju »inteligentnih« tekstilij in kategorizacijo različnih vrst inteligentnih tekstilij. Na kratko opisuje trenutno stopnjo razvoja teh izdelkov in potencial za uporabo ter navaja prednostne standardizacijske potrebe.

General Information

Status
Withdrawn
Publication Date
29-Nov-2011
Withdrawal Date
20-Jan-2026
Current Stage
9960 - Withdrawal effective - Withdrawal
Start Date
09-Dec-2020
Completion Date
28-Jan-2026

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Effective Date
16-Dec-2020
Technical report

TP CEN/TR 16298:2012

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Frequently Asked Questions

CEN/TR 16298:2011 is a technical report published by the European Committee for Standardization (CEN). Its full title is "Textiles and textile products - Smart textiles - Definitions, categorisation, applications and standardization needs". This standard covers: This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a categorisation of different types of smart textiles. It describes briefly the current stage of development of these products and their application potential and gives indications on preferential standardization needs.

This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a categorisation of different types of smart textiles. It describes briefly the current stage of development of these products and their application potential and gives indications on preferential standardization needs.

CEN/TR 16298:2011 is classified under the following ICS (International Classification for Standards) categories: 59.080.80 - Smart textiles; 59.080.99 - Other products of the textile industry. The ICS classification helps identify the subject area and facilitates finding related standards.

CEN/TR 16298:2011 has the following relationships with other standards: It is inter standard links to CEN ISO/TR 23383:2020. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

CEN/TR 16298:2011 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
01-februar-2012
Tekstilije - Inteligentne tekstilije - Definicije, kategorizacija, uporaba in
standardizacijske potrebe
Textiles and textile products - Smart textiles - Definitions, categorisation, applications
and standardization needs
Textilien und textile Produkte - Intelligente Textilien - Definitionen, Klassifizierung,
Anwendungen und Normungsbedarf
Ta slovenski standard je istoveten z: CEN/TR 16298:2011
ICS:
59.080.01 Tekstilije na splošno Textiles in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 16298
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
November 2011
ICS 59.080.99
English Version
Textiles and textile products - Smart textiles - Definitions,
categorisation, applications and standardization needs
Textiles et produits textiles - Textiles intelligents - Textilien und textile Produkte - Intelligente Textilien -
Définitions, catégorisation, applications et besoins de Definitionen, Klassifizierung, Anwendungen und
normalisation Normungsbedarf
This Technical Report was approved by CEN on 24 October 2011. It has been drawn up by the Technical Committee CEN/TC 248.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16298:2011: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Introduction .4
1 Scope .6
2 Terms and definitions .6
3 Functional and smart textile materials .7
3.1 Functional textile materials .7
3.2 Intelligent (smart) textile materials .9
4 Smart textile systems . 14
4.1 Categories . 15
4.2 Examples of “intelligent textile systems” and their functional analysis . 16
5 Recommendations for standardization . 21
5.1 General . 21
5.2 Verification of claimed performances . 22
5.3 Innocuousness . 22
5.4 Durability of properties . 22
5.5 Product information. 22
5.6 Environmental aspects . 23
5.7 Examples of possible standardization of intelligent textile materials and systems . 24
Annex A (informative) Regulations, standards and conformity assessment . 28
Bibliography . 32

Foreword
This document (CEN/TR 16298:2011) has been prepared by Technical Committee CEN/TC 248 “Textiles and
textile products”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
Introduction
Terms like “smart textile” and “intelligent textile” mean different things to different people. However, there is
some common agreement that these are textiles or textile products that possess additional intrinsic and
functional properties not normally associated with traditional textiles.
Although adjectives such as "smart" or "intelligent" are mainly intended for marketing purposes, more
technically correct definitions will not prevent the use of this terminology by textile manufacturers or by the
general public. Nor will the unintended inclusion of “non-smart” products make products any less safe or fit for
purpose.
The standardization of smart textiles or smart textile products or systems is not straightforward because it
involves an overlap between the standardization of the "traditional" textile product, e.g. a fire fighter's jacket,
and the standardization of the additional intrinsic functional properties of the "smart product", whatever they
may be. This overlap can manifest itself in a number of areas that may include:
 Legislation: all textile products should comply with the requirements of the general product safety
directive, which stipulates that only safe products should be put on the European market. Certain textile
product groups, e.g. protective clothing, geotextiles or textile floor coverings, are in addition subject to
specific national and European legislation and it may even be necessary to simultaneously address the
requirements of more than one EU Directive. A "classic" fire fighter's suit should comply with the
requirements of the PPE Directive, usually supported by EN 469, whereas a "smart" fire fighter's suit with
built-in electronic features should e.g. also comply with the applicable provisions of ICT and ATEX
regulations. Conformity assessment will also need to follow the conformity assessment schemes for both
regulations.
 Expertise: the knowledge and experience of standardization for the textile properties and for the
additional properties (temperature sensing, variable thermal insulation properties) may come from
different unrelated standardization groups. To take the above example, there will need to be input from
standardization groups working in the areas of textiles, medical devices and electric or electronic devices.
 Testing: there will be a need to test the additional functional properties to specific textile test standards
and vice versa. Again, with the same example, the electronic elements might have to be assessed for
their resistance to cleaning and the textile elements may need to be tested for electrical safety.
 Unexpected and/or unintended synergies: these might result from the combination of technologies in
smart textiles and should be recognised and addressed by standardization, wherever possible. For
example, the presence of conductive fibres to incorporate a personal stereo into a smart raincoat might
increase the risk of the wearer suffering a lightning-strike in a thunderstorm. This is despite the fact that
neither rainwear nor personal stereos, when separate, need to be assessed against this risk.
The purpose of this technical report is to give advice and information on the considerations that need to be
addressed when writing standards for smart textiles, or applying existing standards to them. This information
may be of use to:
 end-users, in determining whether a product has indeed been fully assessed;
 conformity assessment bodies, as a guide towards assessing products according to the appropriate
standards;
 specification writers, as a guide to writing new specific standards for smart textiles;
 manufacturers of smart textiles, to advise them on appropriate product testing and on suitable ways to
substantiate product claims;
 market surveillance authorities, to help in the assessment of product claims, product safety and fitness for
purpose.
The factual information in this report is available elsewhere in a more comprehensive form and each individual
item will inevitably be common knowledge to at least one group of readers. The aim of this technical report is
to guide readers through those areas, with which they are not familiar, and to direct them towards further,
more specialised reading. In accordance with CEN rules, this Technical Report will be reviewed regularly to
keep it in line with technical and market evolutions.
1 Scope
This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a
categorisation of different types of smart textiles. It describes briefly the current stage of development of these
products and their application potential and gives indications on preferential standardization needs.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
In literature, both the terms ‘smart’ and ‘intelligent’ are used. In this text the two terms are considered
equivalent and hence exchangeable.
NOTE European Directive 2008/121-EC provides definitions of "textile products" and "textile fibres", but these
definitions are not suitable for the purpose of this Technical Report, since they do not distinguish between "textile
products" and "textile materials".
According to the Directive "textile products" are "raw, semi-worked, worked, semi-manufactured,
manufactured, semi-made-up or made-up products which are exclusively composed of textile fibres,
regardless of the mixing or assembly process employed" or
 (a) products containing at least 80 % by weight of textile fibres;
 (b) furniture, umbrella and sunshade coverings containing at least 80 % by weight of textile components;
similarly, the textile components of multi-layer floor coverings, of mattresses and of camping goods, and
warm linings of footwear, gloves, mittens and mitts, provided such parts or linings constitute at least 80 %
by weight of the complete article;
 (c) textiles incorporated in other products and forming an integral part thereof, where their composition is
specified.
2.1
textile material
material made of textile fibres and intended to be used, as such or in conjunction with other textile or non-
textile items, for the production of textile products
2.2
functional textile material
textile material to which a specific function is added by means of material, composition, construction and/or
finishing (applying additives, etc.)
2.3
smart textile material (intelligent textile material)
functional textile material, which interacts actively with its environment, i.e. it responds or adapts to changes in
the environment
NOTE The term "smart textile" may refer to either a "smart textile material" or a "smart textile system". Only the
context, in which the term is used, will determine which one of the two is intended.
2.4
environment (surroundings)
the circumstances, objects, or conditions, which surround a textile material or textile product or the user of that
material or product
2.5
textile system
an assemblage of textile and non-textile components integrated into a product that still retains textile
properties, e.g. a garment, a carpet or a mattress
NOTE The terms "textile system" and "textile product" may be interchangeable in many cases.
2.6
smart textile system
a textile system which exhibits an intended and exploitable response as a reaction either to changes in its
surroundings/environment or to an external signal/input
3 Functional and smart textile materials
3.1 Functional textile materials
3.1.1 General
Functional textile materials can be components of intelligent textile systems and hence functional textile
materials, which are relevant for these intelligent textile systems, will be discussed here. This is illustrated by
the following examples:
Example 1: A textile resistance heater
 Functional textile material: a conductive material forming the basis of a resistance heater in a textile
system.
 Smart textile system: a textile resistance heater as (part of) a textile system, connected to an electrical
power supply which can only be switched on and off manually or a resistance heater as part of a textile
system, connected to an electrical power supply with a regulated power output and equipped with a
temperature sensor as to maintain a constant temperature around the heater.
Example 2: Optical fibres
 Functional textile material: optical fibres used as part of a textile system
 Smart textile system: optical fibres as (part of) a textile system, connected to a light source which can
only be switched on and off manually or optical fibres as part of a textile system, connected to a light
source with a regulated power output and equipped with a sensor to adjust the illumination level to the
amount of light present due to other light sources in the surroundings of the textile system.
3.1.2 Electrically conductive textile materials
Electrically conductive textile materials conduct an electrical current or supply an electric field to a device.
Electrical conduction is the movement of electrically charged particles through an electrical conductor, called
an electric current. The charge transport may result as a response to an electric field or as a result of a
concentration gradient in carrier density, i.e. by diffusion.
-2
A material is considered 'electrically conductive' if it has a specific conductivity (resistivity) of > 10 S/m
4 2
(<10 Ω·cm). A material is considered to have a 'metallic conductivity' if it has a specific resistivity of > 10 S/m
(<10 Ω·cm). The materials with the highest specific conductivity are metals. Some polymers and ceramics can
also have metallic conductivity, e.g. intrinsically conductive polymers (e.g. doped polyaniline) or indium tin
oxide (ITO).
3.1.3 Thermally conductive textile materials
Thermally conductive textile materials conduct heat. The transfer of thermal energy in a substance is due to a
temperature gradient, i.e. from a region of higher temperature to a region of lower temperature, acting to
equalize temperature differences.
Metals have thermal conductivities above approximately 20 W/(m·K) and are considered to be very good
thermal conductors. Their thermal conductivity increases with their electrical conductivity. There are also non-
metallic elements and compounds that are (very) good thermal conductors (e.g. carbon and boron nitride).
Applications in intelligent textile systems can be as a heat sink, e.g. for cooling electronic components.
3.1.4 Thermally radiative (emissive) textile materials
Thermally radiative (emissive) textile materials radiate heat, i.e. they emit electromagnetic radiation in the
infra-red range of 750 nm to 100 µm from their surface due to their temperature.
Thermal radiation (emission) can be utilized in the form of a resistance heater, where the resistance of a
conductor is used to heat the conductor to a sufficiently high temperature to generate heat radiation or as a
heat exchanger, e.g. a pipe with hot air or hot water flowing through it.
Applications in intelligent textile materials are as thermal heaters, as described in 3.1.1.
3.1.5 Optically conductive textile materials
Optically conductive textile materials transport (visible) light, i.e. electromagnetic radiation in the range of
400 nm to 750 nm.
Optical fibres from glass or plastic keep the light in their core by total internal reflection, i.e. the fibre acts as a
waveguide. Optical fibres are widely used in fibre-optic communications, which permits transmission over
longer distances and at higher bandwidths (data rates) than other forms of communications. Fibres are used
instead of metal wires because signals travel along them with less loss, and they are also immune to
electromagnetic interference.
Fibres are also used for illumination, and are wrapped in bundles so they can be used to carry images, thus
allowing viewing in tight spaces. Specially designed fibres are used for a variety of other applications,
including sensors and fibre lasers.
3.1.6 Fluorescent textile materials
Fluorescence is the molecular absorption of a photon, followed almost instantaneously by the emission of a
less energetic photon. As the emitted photon is of lower energy than the absorbed photon, the emitted light
will be of longer wavelength than the absorbed light, which allows e.g. to turn UV radiation into visible light.
Fluorescence is used in high visibility clothing for safety purposes. Fluorescent textile materials are available
in a variety of colours from red to blue-violet. A variety of organic and inorganic materials show fluorescence.
3.1.7 Phosphorescent textile materials
Phosphorescence is the molecular absorption of a photon, resulting in the formation of an excited state,
followed by the emission of a less energetic photon. Since the emitted photon is of lower energy than the
absorbed photon the emitted light will be of longer wavelength. The lifetime of the excited state in
phosphorescent materials can be very long, in the order of hours. This means that once activated,
phosphorescent materials will continue to emit light for hours without any external power supply. This makes
them suitable for emergency lighting in the case of power interruptions or for watches, toys, apparel, giving a
'glow in the dark' effect.
Examples of phosphorescent materials are e.g. doped (mixed) sulphides (ZnS, (Cd, Zn)S, (Ca, Sr)S) or doped
(mixed) oxides (SrAl O ) but can also be organic molecules.
2 4
3.1.8 Textile materials releasing substances
These textile materials release substances at a molecular level under the influence of an external stimulus.
The substances used for this purpose are pharmaceuticals, cosmetics, fragrances, etc. They are bonded to
the textile structure by micro-encapsulation or by surface bonding.
The micro-encapsulation technique makes use of small capsules, in which the substance to be released is
enclosed. When the shell of these capsules is pierced due to an external stimulus, the substance is released.
The different stimuli that can cause piercing of the shell include mechanical force, heat, pH and contact with
water.
The surface bonding technique makes use of substances (loosely) bonded to the surface of the textile
material and released during the use of this material. The nature of the bonding and the surroundings of the
material will determine the release rate.
3.2 Intelligent (smart) textile materials
3.2.1 General
In this subclause, different intelligent (smart) textile materials will be described. Some of the textile materials
may already be composite systems. The described textile materials may be used on their own or in
combination with other (non)smart textile materials or used in textile systems. The latter is described in
clause 4.
NOTE Some of the smart functionalities may also be achieved by non-textile materials. Therefore, we will be referring
to textile materials to clearly make the distinction.
Table 1 provides an overview of the most common stimulus-response pairs and the corresponding effect
materials or structures can exhibit.
Table 1 — Overview of stimulus-response effects (adapted from [1])
Stimulus Response
Optical Mechanical Chemical Electrical Thermal
Optical
Photochromism  Photovoltaic/
photoelectric
effect
Mechanical Piezochromic Dilatant, Controlled Piezo-electricity Friction
Thixotropic, release
Auxetic
Chemical Chemiluminescence, Shape memory, Controlled Exo/endotherm
Solvatochromism, Super-absorbing release reactions
Halochromisms polymers,
Sol/hydrogel
Joule/coulombic
Electrical Electrochromism, Inverse piezo- Electrolysis
heating
Electroluminescence, electricity,
Peltier effect
Electro-optic electrostriction
Electro-osmosis
shape memory
Thermal Thermochromism, Shape memory Seebeck effect, Phase change
Thermo-opacity Pyroelectric
Shape memory
Magnetic
magnetrostriction
3.2.2 Chromic textile material
Chromic materials is the general term referring to materials whose absorption, transmission and/or reflection
of light changes due to an external stimulus. The result is a different colour impression.
Chromic materials can be classified depending on the external induction stimulus, e.g. light (photochromic),
heat (thermochromic), pressure (piezochromic), enzymes (biochromic). It goes beyond the scope of this report
to list all possible chromic effects or to discuss them in detail.
One commercial application of a thermochromic textile material is baby clothing which shows a change in
colour when the baby has developed a fever. Other applications envisioned for safety clothing are the use of
chromic textile materials for indicating exposure to chemicals or radiation.
3.2.3 Phase change textile material
A phase change material (PCM) is a substance which is capable of storing and releasing large amounts of
energy in the form of latent heat, at a specified temperature range (range of phase transformation) during
which the material changes phase or state (from solid to liquid or from liquid to solid). This energy (heat) is
absorbed or released when the material changes from solid to liquid (or the other way around), thus buffering
any external temperature change by evoking a phase transition in the material.
Classic PCMs are water, hydrated salt complexes and saturated hydrocarbons (where the length of the chain
will determine the melting point). Depending on the nature of the phase change, e.g. when formation of a
liquid phase is involved, micro-encapsulation will be required. The choice of material or composite will depend
on the temperature to be buffered.
The most common method today to produce phase change textile materials is by coating or impregnating
fibres or fabrics with a polymeric binder containing micro-encapsulated PCMs. Alternatively, micro-
encapsulated PCMs may be incorporated into fibres during the fibre spinning or filling of hollow fibres. They
may also be laminated as a PCM containing polymeric film onto a textile structure.
Space suits and gloves were the first application of phase change materials (PCM), but nowadays PCMs are
also used for consumer products to improve the thermal comfort of active-wear garments and clothing textiles.
During a sports activity, the thermal stress is mainly due the disequilibrium between the heat produced by the
human body during an effort, and the heat released into the environment. When PCMs are encapsulated on
underwear, during the same activity a larger amount of the human heat will be released to the environment.
3.2.4 Shape change (shape memory) textile materials
These materials change in shape, size or internal structure upon an external stimulus, e.g. temperature, UV
light, moisture, magnetic field, pH value. The shape change can have a one-way or a two-way effect.

A one-way material has a preformed structure, which returns in a non-reversible way to its original, not-
preformed state after receiving an external stimulus.
A two-way material or composite can be cycled between two different preformed states by receiving opposing
external stimuli, e.g. a higher and lower temperature.
Shape memory materials can be:
 polymers with a combination of permanent physical or chemical cross-links, integrated into a mobile
matrix, which is able to store mechanical deformation energy until recovery is activated by an external
stimulus;
 metal alloys switching between two different crystal structures upon a thermal impulse, e.g. Nitinol, or
 composites of shape-memory-materials and materials providing an elastically restoring force in one unit
(e.g. artificial muscles).
Shape memory materials can be implemented in textile systems in the form of yarns, i.e. in the bulk of the
textile structure or as a coating on a fabric, e.g. creating a membrane. Applications can be textile systems
adjusting their shape, e.g. a garments reducing its length when exposed to heat; or a membrane adjusting its
porosity, e.g. to adjust the water vapour transmission rate.
3.2.5 Super-absorbing polymers and gels
Super-absorbing polymers and gels absorb and retain extremely large amounts of liquid relative to their own
mass resulting in strong swelling and gel formation. Water absorbing polymers (hydrogels) absorb aqueous
solutions through hydrogen bonding with water molecules. The ability to absorb water depends on the
presence of ions in the water, being 500 times its weight (30 to 60 times its volume) for distilled or deionised
water, but only 50 times its weight for a 0.9 % saline solution.
The total absorbency and swelling capacity are controlled by the type and degree of cross-linking in the
polymer. A low-density cross-linked polymer has a higher absorbent capacity and a softer and more cohesive
gel is formed. High cross-link density polymers exhibit lower absorption capacity but the gel strength is firmer,
maintaining its shape under low pressure.
Examples of the use of super-absorbing polymers are hygiene products, blockage of water penetration in
underground power communication cables, horticultural water retention agents, spill and waste control,
artificial snow for motion picture and stage production and filtration.
3.2.6 Auxetic textile materials
Auxetic materials or composites harden and laterally expand upon elongation. This phenomenon is caused by
the macro-structure or micro-structure of the material and not by its chemical composition. Such materials
have a so-called negative Poisson ratio.
Some auxetic textile materials contain on a micro-scale both temporary, relatively weak bonds (e.g. hydrogen
bonds), which can be broken and restored (slipping from one to the other) under a low shear force and stable
bonds, which, under a high shear force, will counter the full load of the force, resulting in a 'stiff' behaviour.
Other auxetic textile materials are based on the use of materials with diverging properties, e.g. a textile yarn
comprising a thicker, elastic cord entwined with a thinner, stiffer cord. When tensioned the system will change
to the thin, stiff cord being entwined by the thicker, elastic cord and the total diameter will be increased as
compared to the relaxed state.
Auxetic textile materials are intended for improved energy absorption and fracture resistance. Examples of
auxetic textile applications are blast resistance, window covering, military tents, and hurricane defence.
Examples of auxetic foam materials are found in sound and shock absorption, medical engineering, filtration
of biological fluids and process engineering.
3.2.7 Dilating and shear-thickening textile material
These materials show an increase in viscosity with increasing shear rate, i.e. they will become hard upon
impact and remain soft under low force movement.
A dilatant effect occurs when closely packed particles are combined with enough liquid to fill the gaps between
them. At low flow velocities, the liquid acts as a lubricant, and the dilatant flows easily. At higher flow
velocities, the liquid is unable to fill the gaps created between particles, friction strongly increases, resulting in
a sudden increase in viscosity.
Applications in textiles are found in protective clothing against mechanical impact, e.g. body armour, and in
traction control. An example is a soft silicone coating on a fabric, which hardens under impact, thus damping
the force of the blow.
3.2.8 Piezoelectric textile material
The piezo-electric effect consists of a separation of electrical charges across a material in response to an
applied mechanical deformation. This effect can also be inversed, i.e. a mechanical deformation is generated
in response to an applied electric field.
Applications of the piezo-electric effect are found in insulating materials having a non-centrosymmetric crystal
lattice (e.g. quartz, PZT, PVDF). In order to utilize the charge separation by mechanical deformation or to
realize the mechanical deformation by applying an electric field, the piezo-electric material needs to be
positioned between two electrodes. For polycrystalline materials to exhibit the piezoelectric or inverse
piezoelectric effect, the individual crystallites need to be aligned, which is done by applying a high electric field
at elevated temperatures.
Piezoelectric materials can be used to develop textile materials for strain or acceleration sensing as well as for
energy production utilizing mechanical deformation (e.g. in shoes).
3.2.9 Electroluminescent textile materials
This refers to textile materials emitting light in response to an electric current passing through them or to a
strong electric field being applied to them. In these structures the electroluminescent layer needs to be
sandwiched between two electrodes, the top one being transparent for transmission of the emitted light.
For the electroluminescent layer most commonly inorganic or organic semiconductors (thin film or powder) are
used, together with a dopant (additive) to define the colour, or inorganic materials such as ZnS, doped with
Cu, Ag, or Mn.
Electroluminescent textile materials can operate at low voltage and low current. They can be used to provide
lighted displays on apparel or canvasses for leisure or advertising purposes.
3.2.10 Thermo-electric textile materials
These materials will generate an electric field when a thermal gradient is applied. The material needs to show
a good electrical conductivity but a poor thermal conductivity in the direction of the thermal gradient.
In these structures the thermo-electric material needs to be sandwiched between textile electrodes and a
good heat transfer needs to be ensured at the external surfaces.
Thermo-electric textile materials applications are power generation and refrigeration.
3.2.11 Photovoltaic textile materials
In photovoltaic (photoelectric) materials the impact of a photon results in the transition of an electron from the
valence band to the conduction band of a semiconductor.
Photovoltaic materials, as used in photovoltaic cells, consist of a top electrode, a p-type semiconductor/ n-type
semiconductor junction and a bottom electrode. Illumination of a photovoltaic cell results in the generation of
charges, i.e. building up of a voltage between the two electrodes. Hence, the device can act as a power
supply.
Examples of photovoltaic materials are doped Si and dye sensitised oxide semiconductors (TiO , ZnO). Their
major application field is in solar cells (absorption of sunlight), as grid independent power supply.
3.2.12 Electrolytic textile materials
An electrolyte is a substance containing free ions that behaves as an electrically conductive medium (based
on ion conduction). Electrolytes are used as a part of a battery. Placing a metal into an electrolyte will result in
the deposition of ions on the electrode or dissolution of ions from the electrode into the electrolyte, i.e. the
formation of a galvanic half cell. Two galvanic half cells are combined to form a battery.
Fully textile based batteries have not been developed yet, but are anticipated as they will be much lighter
weight and retain textile properties as compared to current battery technology. The latter is usually a major
drawback in textile systems requiring an input of electrical energy.
3.2.13 Capacitive textile materials
Capacitive textile materials have the ability to store electrical charges. A typical capacitor consists of an
insulating material placed between two conductive materials (electrodes). When an electrical field is applied to
the insulating material, negative and positive charges will be separated and stored at the opposite surfaces of
the material.
Capacitive textile materials can be created by multilayer weaving or embroidering, laminating multilayer
structures or printing multi-layers of conductive ink.
4 Smart textile systems
Figure 1 — Flow chart for characterizing an intelligent textile system, also giving guidelines for later
standardization efforts
4.1 Categories
4.1.1 General
An intelligent textile system is basically composed of:
 Actuator(s), completed by possible sensor(s)
 Information management device
The information within the intelligent textile system can be controlled and/or managed by electronic device(s)
(such as a processor). Such textile systems are also called "e-textiles" or "textronics".
An intelligent textile system can be characterised by two functions: the energy function and the external
communication function. External communication can be unidirectional or bidirectional, and implies a possible
interaction with human intelligence.
Based on these two functions, depending on whether they are present or not, four different categories can be
determined (see Table 2 and Figure 1).
Table 2 — Categories of intelligent textile systems
Without energy function With energy function
Without communication function "NoE-NoCom" "E-NoCom"
With communication function "NoE-Com" "E-Com"

Intelligent textile systems "with energy function" are based on the presence of an internal power supply
device fed by elements of the system capable of producing and supplying energy to it. Energy sources outside
the textile system are usually needed for ensuring the continuity of the energy function.
Intelligent textile systems "without energy function" are not equipped with an internal energy supply device,
but may require an external supply of energy, usually in form of the stimulus.
Intelligent textile systems "with communication function" include the presence of mono- or bidirectional
means of communication with their environment. The communication may be intended for direct perception by
humans, e.g. visual information, sound, odours, etc., or for detection by electronic devices (emission of
phonic, electromagnetic, photonic waves) relaying the information towards man.
Intelligent textile systems "without communication function" are characterized by the absence of external
communication with their environment/ surroundings. This does not exclude internal communication, e.g. in a
self-regulating system.
4.1.2 Systems without energy or communication function (NoE-NoCom)
Examples of this category are:
 Garments equipped with shape memory or phase change material: the thermal energy is externally
supplied from the temperature of the environment. A temperature rise or drop will be the stimulus leading
to the modification of the material's behaviour.
 A LED Curtain: the energy is supplied by the external electrical power grid. The electric current is the
stimulus that leads to the emission of photons (lamp)
In both examples there is no internal energy supply source or communication with the external environment.
4.1.3 Systems with energy function, but without communication function (E-NoCom)
Examples of this category are:
 A backpack with a battery connected to a photovoltaic device. The battery needs to be replaced when it
runs empty, but this replacement is delayed thanks to the photovoltaic device transforming photonic
energy (light) into electricity.
 A shoe with a battery connected to an electro-mechanical transducer. The battery needs to be replaced
when it runs empty, but this replacement is delayed thanks to the electric energy produced by the electro-
mechanical device.
Both examples show systems, which comprise an internal energy source (battery), completed by an external
energy source. Neither of them is designed for communication with the external environment.
4.1.4 Systems with communication function but without energy function (noE-Com)
Examples of this category are:
 Breathing sensor on a hospital patient. The mechanical stimulus (deformation of material) acts on a
sensor which transmits an electric signal to the system, leading to the emission of radio waves towards
the environment, received by a detector used by a physician.
 A baby pyjama dyed with a thermochromic pigment for indicating a raise in body temperature of the baby
(development of a fever). When the temperature of the baby rises above a certain threshold the dye
changes colour, giving a visual warning signal to the observer, e.g. a parent.
Both examples do not include an internal energy supply source, although an external source is present. These
systems include a means of communication with the external environment.
4.1.5 With energy and communication function (E-Com)
Examples of this category are:
 Sensing and warning system for chemical plant workers. The chemical stimulus (molecule) acts on a
sensor, which will transmit the chemical information internally to the system. The information is then
transmitted towards the outside environment as a change of colour or as a sound, perceived by the
human eye or ear.
 Thermal Detector in a fire fighter's jacket. The thermal stimulus (temperature) acts on the thermal sensor
which transmits the internal information to the system (electric signal), leading to the emission of a light
signal, perceived by the human eye.
Both systems make use of an internal energy supply (battery) and include a means of communication with the
external environment.
4.2 Examples of “intelligent textile systems” and their functional analysis
4.2.1 Medical application: monitoring of health situation
Medicine is expected to clearly benefit from intelligent textile technologies. These applications cover a broad
and complementary range of explorations (i.e. a diagnosis of heart disease), prevention (i.e. biofeedback) and
treatment/healing (i.e. wearable orthoses, drug delivery). Future medical applications may include sensors,
that will non-invasively measure blood gases (CO, SO , CO ) and vital signs.
2 2
Wearable monitoring systems with integrated sensors can be separated into two categories:
 Systems with conventional sensors integrated by textile technologies in a textile-based material
 Systems with textile-based structures used as sensors to measure vital parameters of the human body.
The vital parameters can be separated in electrical, mechanical and other parameters. For monitoring the
EMG, ECG, or EEG the electric stimulus acts on the conductive textile by a galvanic skin-contact or by a non-
contact capacitive principle, which will transmit internal (electric) information to the system leading to the
emission of electromagnetic waves (radio waves) towards a detector device used by a physician.
Mechanical signals like breathing rate can be measured by elastic conductive ribbons which change their
resistance under strain. The mechanical stimulus (deformation of material) acts on the deformation sensor
(elastic conductive ribbon) which will transmit internal information (electric) to the system leading to the
emission of electromagnetic waves (radio waves) towards the environment, detected by a detector device
(used by a physician).
Beside the sensor, the wearable monitoring system has to contain at least a storage device. Devices for data
analysis, data transport and actuator devices for warning or defibrillation functions can complete the
monitoring system.
Considering that in this example the system is autonomous, this “intelligent textile system” belongs to the "E-
Com" category:
 “with energy function” because the concept is based on the presence of an electric battery as power
source. The replacement of the battery is necessary when the reserve is depleted.
 “with communication function” because the concept is based on communication with the environment, in
the form of emission of an electromagnetic wave suitable for electronic monitoring devices.

Key
1 Communication
2 Sensors
3 Processors
4 Actuator
5 Energy supply
Figure 2 — Example of a wearable textile system
4.2.2 Occupational safety application: work wear and protective clothing
These systems bring together features such as sensors, connections, transmission systems, power
management etc. The integration of intelligent textile technologies into work-wear or protective clothing can
result in such systems being able to gather, present and transmit information about the wearer and his or her
immediate environment.
For example, protective clothing incorporating such textile systems could potentially gather information on:
 wearer position, either globally by GPS or locally by reference to one or more base-stations;
 wearer activity, monitored by accelerometers integrated into various parts of a garment;
 physiological data including the wearer’s body temperature, pulse, blood oxygen level and breathing rate
(see also 4.2.1, medical monitoring application);
 environmental temperature measured using textile sensors. In the case of fire-fighters’ PPE this might
include information on the direction of sources of radiant heat relative to the wearer;
 chemical hazards in the environment including monitoring of toxic chemicals and detection of explosive
atmospheres;
 electromagnetic hazards in the environment, including monitoring of various forms of electromagnetic
radiation;
 the status of the smart system itself. For example this might include data on the state of charge of an
incorporated flexible lithium-ion polymer battery or confirmation that sensors are operating correctly and
mutually consistently.
Such information can then either be transm
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