smart textile

Smart Textile
Smart textiles are defined as textiles that can sense and react via an active control mechanism to environmental conditions or stimuli, such as mechanical, thermal, magnetic, chemical, electrical, or other sources. They are able to sense and respond to external conditions (stimuli) in a predetermined way.

1. Smart Textile
Smart textiles are defined as textiles that can sense and react via an active control mechanism to
environmental conditions or stimuli, such as mechanical, thermal, magnetic, chemical, electrical, or other
sources. They are able to sense and respond to external conditions (stimuli) in a predetermined way.
Smart textiles are also known as E-textiles or intelligent textiles, electro active textiles, wearable electronics
and textronic textiles depending on the approach.
E-textiles also known as smart garments, smart clothing or electronic textiles, that are manufactured from
smart fabrics consists of digital components such as a battery and a light (including small computers), and
other required electronic devices to be embedded in them.
Components in smart textile
Three components may be present in smart textiles (materials)
• Sensors
• Actuators
• Controlling units
The sensors provide a nerve system to detect signals. Some of the materials act only as sensors and some as
both sensors and actuators. Actuators act upon the signals and work in coordination with the controlling unit
to produce an appropriate output.
Functions of the components in smart textile
Sensors
Sensors provide a nerve system to detect signals
Actuators
Actuators act upon the signals and work in coordination with the controlling unit to produce an appropriate
output.
Controlling units
Controlling units produce an appropriate output
Classification of smart textiles
Smart textiles are classified into three categories depending on functional activity, as follows:
• Passive smart textiles
• Active smart textiles
• Very or ultra smart textiles

2. Passive smart textiles
Passive smart textiles are materials which only sense the environmental conditions or stimuli. They are just
sensor. They show up what happened on them.
Optical fiber embedded fabrics, UV protective clothing, multilayer composite yarn and textiles, plasma
treated clothing, ceramic coated textiles, conductive fibers, fabrics with optical sensors, are some examples
of passive smart textiles.
Active smart textiles
Active smart textiles are the textile materials that can both sense and respond to the external conditions or
stimuli. The actuators are integrated in the passive smart textile. It becomes an active smart textile as it may
respond to a particular stimulus.
Examples:
Phase change materials and shape memory materials, heat sensitive dyes etc. convert the textiles as active
smart textiles. The temperature aware a shirt automatically rolls up the sleeves when body temperature
becomes elevated.
Ultra or very smart textiles
Very smart textiles are the third generation of smart textiles, which can sense, react, and adapt themselves to
environmental conditions or stimuli. They are the highest levels of smart textiles. These may deal actively
with life threatening situations (battlefield or during accidents) or to keep high levels of comfort even during
extreme environmental changes. These very smart textiles essentially comprise of a unit, which works like
the brain; with cognition, reasoning and activating capacities.
For example, spacesuits, musical jackets, I-wear, data wear, sports jacket, intelligent Dress, smart clothes,
wearable computer etc.

General methods of incorporating smartness into textiles
Textile to behave smartly it must have a sensor, an actuator (for active smart textiles) and a controlling unit
(for very smart textiles). These components may be fiber optics, phase change materials, shape memory
materials, thermo chromic dyes, miniaturized electronic items etc. These components form an integrated part
of the textile structure and can be incorporated into the substrate at any of the following levels
• Fiber spinning level
• Yarn/fabric formation level
• Finishing level
The active (smart) material can be incorporated into the spinning dope or polymer chips prior to spinning e.g.
lyocell fiber can be modified by admixtures of electrically conductive components during production to
make an electrically conductive cellulosic fiber. Sensors and activators can also be embedded into the textile
structure during fabric formation e.g. during weaving or knitting. Many active finishes have been developed
which are imparted to the fabric during finishing. The electronic control units can be synchronized with each
other during finishing. Techniques such as microencapsulation are generally preferred for incorporation of
smartness imparting material in the textile substrate. However the correct material and the correct method
must be selected; based on a variety of considerations.

3. Steps of functioning of smart textiles
1. Sensing of stimuli
2. Data processing
3. Actuation
4. Storage
5. Communication
Working principle of smart textiles

Working procedure of a smart textile
1. Sensing
 Basically, sensing is the function of transforming a signal into another signal that can be read and
understood by a predefined reader which can be a real device or a person.
 For real devices all the signals should be ultimately converted into electrical ones.
2. Data Processing
 Data processing is one of the components that are required only when active processing is necessary.
 The electronics are used for data processing are now available in miniaturized and even in flexible
form.
 Problems need to be overcome before imparting textile material for this function are; fastness to
washing, deformation, interconnections etc.
3. Actuation
 Actuators respond to an impulse resulting from sensor function, possibly data processing.
 Actuators make things move, release substances, make noise and many more

4. 4. Storage
 Sensing, data processing, actuation, communication usually need energy, mostly electrical energy.
 For efficient energy management there should be an appropriate combination of energy supply and
energy storage capacity.
 Here sources of energy are instance body heat, mechanical motion, radiation etc.
 Phase change materials or PCM acts as energy storage.
5. Communication
 Controlling unit follow the instructions by communicating with the software that is previously
prepared to get the particular output.

Applications of smart textiles
Smart textiles find a wide spectrum of applications ranging from daily usage to high-tech usage. Now we can
review various important applications of such textiles. We would consider textiles used for the following
broad categories:
• Medical applications
• In constructions sector
• Sports
• Comfort wear
• Heat protection
• Military applications
• Computing textiles
• Fashion
• Aviation
• Space research
It should be noted that a textile mentioned in one category can find use in other categories as well. For
example, chameleonic textiles (textiles that change color) are discussed as fashion wear. But they are of
profound significance in the military since uniforms made out of them can help in camouflaging to protect
the soldier.

5. Smart textiles in the field of medical textiles
Sensors for recording human physiological parameters
This clothing, also called life shirts, was popularized by the American Sensatex company, and is used as an
undershirt. Optical fibers are spirally plaited into its structure. The whole undershirt has been made with a
special weaving technique, in one piece, without any cuttings or seams. The main task of this intelligent shirt
is to monitor human physiological parameters such as temperature, pressure, pulse and heartbeat etc.
They can diagnosis various body parameters such as ECG. These fabrics can also measure the presence of
poisonous gases in the air.

Smart textiles in construction sector
The fiber sensors laid in composite structures can be used to:
 Monitor strain and temperature throughout a composite structure such as bridge
 Detection of crack in composite structure such as building, dam or bridge
 Monitor the structure of any other composite (bridge, building, dam etc )

Smart textiles in sports
Benefit of smart shoe or socks or smart sole
 The socks made with textile sensors are paired with a Bluetooth-enable anklet that sends information
on distance, speed, altitude, steps etc to the apps or any other device.
 It is also possible to know how many calories are burning during walking or exercise.
 Global Positioning Systems (GPS) incorporated into walking shoes which allow the user to be
tracked by mountain rescue services.
 They can be used to monitor the children during play.
Benefits of smart gloves or helmet
 Gloves that contain built in LED’s emitting light to change the direction of movement especially at
night.
 Helmet that contain built in LED’s emitting light so that a cyclist can be seen from the long distance
in the dark.
 Moreover, the smart textile products will help to reduce the accidents

6. Benefits of smart athlete suit
 This suit has several layers with heat sensor and micro-components embedded in apparel to measure
the signal
 Training data can be observed and recorded by an athlete instantly during practice.
 The suit can monitor the vital signs of the wearer such as heart rate, respiration rate, temperature,
activity and posture.
 Athletic performance can be improved by a sportsman by observing the results of his performance.
 From outside it measures the weather and from inside it monitors wearer’s biophysical state by
analyzing the internal and external characteristics.
 The jogging suit can suggest the duration and intensity of exercise.
 A microchip card inside the suit can sense when jogger is tired and suggest him to stop or rest.

Breathability of fabric
This is the ability of a fabric to let air to pass through so that perspiration can evaporate.
Breathable fabric allows moisture to pass through the fabric from our body. Breathability is an easy way of
saying “moisture vapor transmission rate”. MVTR is the measure of how quickly (or how slowly) moisture
passes through a fabric or other substance.
Coolmax
®
fabric
Coolmax
®
is a lightweight engineered fabric made of 4 or 6 channel polyester fibers, which form a transport
system with increased surface area.
This will help to pull moisture away from the skin to the outer layer of fabric and keeps the wearer cool and
dry.
Coolmax
®
is a high-tech fabric specifically and uniquely manufactured to keep users dry, cool and
comfortable when they start to perspire.
Coolmax
®
is a trademark of INVISTA Apparel and has been available in the market since 1986.

7. How it works
 Coolmax
®
fabric pulls moisture away from the skin.
 Coolmax
®
fabric absorbs and spreads moisture out across fabric to enhance evaporative drying rate.
 Air moves in to keep the body cool and dry.
Application of Coolmax
®
fabric
The fabrics used by the athletes who perspire heavily during their workouts, the product keeps them dry by
providing breathability and allowing perspiration to evaporate quickly away from the fabric.
The fabrics are mainly used for the purposes that require a high level of exertion, such as running, bicycling,
and aerobics.
Gore-Tex fabric
 Gore-Tex is well known for its protective rain water.
 The basic rain wear consists of two layers where the outer layer is typically nylon or polyester which
provides strength
 The inner layer is polyurethane and provides water resistance at the cost of breathability

Figure: Gore-Tex fabric and membrane of Gore-Tex fabric
How does Gore-Tex fabric works
 The Gore-Tex membrane has 9 billion pores per square inch with each pore size 20,000 times
smaller than a water droplet.
 So the water droplets do not pass through the tiny pore.
 But the pore diameters are about 700 times larger than a water vapor molecule and they allow
perspiration and water vapor to escape from the inside.

8. Application of Gore-Tex fabric
It is most commonly used as a waterproof material in the rain jackets, ski jackets, gloves, boots, ski pants and
a wide variety of other apparel applications in which increased airflow and high porosity are desired.

Phase Change Material (PCM) or Outlast material
 It protects from cold and hot weather.
 These protective clothes are used to maintain the body temperature in comfortable zone.
 PCM material has paraffinic hydrocarbons, which are added to man-made fibers during spinning or
microencapsulated during finishing.
 This will help by keeping the body at constant temperature, cool in hot conditions and warm in cold
climate.

Figure: Working principle of Phase Change Materials (PCM)
Application of PCM material in shoe
As Outlast
®
technology proactively responds to changes in foot temperature. It absorbs and stores as well as
releases heat to reduce sweat and odor. It’s a benefit that provides greater comfort and healthier feet all day
long. From socks and insoles to sneakers, shoes, boots and safety gear, the Outlast
®
technology developed
for NASA can keep the customers just as comfortable. Puma, Adidas use this technology.

9. Speedo fabric (shark skin)
 Speedo “ Fastskin” swimsuit was developed using V-shaped fibers which mimic the ridges found
on the skin of a shark.
 The sharkskin is made from specially developed polyamide and lycra fiber coated with Teflon to
prevent water penetration.
 This fabric is knitted with 3-dimenssional V-shaped groove with 3-D knitting principle.
 With help of this V-shaped groove, the friction between water and swimmer is negligible and
drag up to zero.

Denticles on Shirk Skin Speedo Fastskin swimwear mimicking the Shirk
denticles
Purpose or Functions of Speedo Fabric
The fabric increases the efficiency of the swimmer by 8-10%.
These fabricated textiles are water repellent, chlorine resistant and super-quick to dry.

UV protective fabric
 The protection of textile materials from ultraviolet radiation of sun is termed as UV protection factor
(UPF).
 The larger the SPF, the more protective the fabric is to UV radiation.
 In Europe and Australia the SPF is referred to as the ultraviolet protection factor (UPF).

Effect of long-term exposure to sun i.e. UV ray
 Acceleration of skin ageing
 Photodermatosis (acne)
 Phototoxic reactions to drugs

10.  Erythema (skin reddening)
 Sunburn
 Risk of melanoma (Skin cancer)
 Eye damage (Opacification of the cornea)
 DNA damage

11. Method of UV protection in Textiles
1. Nano finishes
2. Using UV absorbers
3. Application of colors
Nano finishes
 Application of nano particles of diameter between 1 and 100 nm.
 ZnO, TiO2 are used as nano particles to absorb the UV radiation.
 ZnO, TiO2 are non toxic, compatible with human skin, chemically stable under both high temp. and
UV ray.
 Easily available and cheaper sources

Recipe for UV protection finishing
UV absorber : 80 – 120 gm/l
pH (maintain by CH3-COOH) : 4.5 – 5
Drying temperature : 100
0
c
Curing temperature : 130 – 170
0
c
Curing period : 1 – 4 minutes


Figure: Process sequence of pad-dry-cure

12. Smart Textile for entertainment
Smart Jacket

 It has touch sensitive keyboard embroidered directly into the fabric using conductive thread
 Several keys can be functioned simultaneously
 The jacket is entirely battery operated, with powered speakers in the pockets

Smart textiles in space suit
 A space suit is a garment worn to keep a human alive in the harsh environment of outer space,
vacuum and temperature extremes.
 Advanced suits better regulate the astronaut’s temperature with a liquid cooling and ventilation
garment to contact with the astronaut’s skin, from which the heat is dumped into space through an
external radiator

13. Criteria should be fulfilled by smart fabrics or textiles
 Light weight
 Durable
 Washable
 Integratable with human body
 Pierce resistant
 Tracking/ Communicaiton systems
 Monitoring systems
 Usable in security authentication