26
D. K. Subbiah et al.
4.2 Protective Fabrics Against Electromagnetic Radiation
A substantive growth in electronic devices and equipment has raddled significant
attention because they expose undetectable electromagnetic pollution, which could
otherwise cause voluminous problems to the environment. In particular, the elevation of electromagnetic fields and harmful ultraviolet radiations in the atmosphere
severely affects humans resulting in health-related problems such as skin cancer
[121], cataracts [122], eye damage [123], aging [124], tanning of the skin [125],
damage to the cornea [126], to name a few. Hence, there is a pressing need to protect humans from radiation-induced waves (EM and UV rays) for which this section
discusses the nanostructured fabrics including protective finishing against the same.
4.3 Electromagnetic Waves
“Electromagnetic radiation is a form of energy that propagates as both electric and
magnetic waves and travelling in packets of energy called photons” [127]. Electromagnetic emission comprises of a wide spectrum of wavelengths that includes
infrared, ultraviolet, radio waves, microwaves, X-rays and gamma rays, which in turn
impacts severe physical damage, changes in the nerve cell performance and stimulating nerves and muscles. In this context, we are in a situation to protect ourselves
from these hazards and the same can be achieved by “shielding”. Through shielding,
one can reduce the exposure of high intensity electromagnetic waves by blocking
them with using conductive materials, magnetic materials and nanocomposites as
barriers.
Electromagnetic Waves Shielding Mechanism
When an electromagnetic wave propagates through a body, it could interact in three
different phenomena based on its strength.
1. Attenuated absorption
2. Attenuation due to reflection
3. Attenuation due to successive internal reflections.
Usually, the blocking mechanism in electromagnetic shielding is based on two
significant functions, namely, reflection phenomena by the conductive medium and
absorption phenomena in the volume of conductive surface.
When an electromagnetic wave strikes the conductive surface, it encounters two
types of losses, namely reflection and absorption [128, 129]. A few portions of the
waves get reflected while the remaining waves get transmitted. These waves also
gets attenuated when they pass through the conductive surface, which is depicted in
Fig. 12 [130]. This combined loss will determine the shielding effectiveness. Though
the barrier causes the absorption phenomena, the absorbed electromagnetic energy
can be converted into thermal energy. In general, shielding of EM waves can be
classified into two groups based on its material classification:
D. K. Subbiah et al.
4.2 Protective Fabrics Against Electromagnetic Radiation
A substantive growth in electronic devices and equipment has raddled significant
attention because they expose undetectable electromagnetic pollution, which could
otherwise cause voluminous problems to the environment. In particular, the elevation of electromagnetic fields and harmful ultraviolet radiations in the atmosphere
severely affects humans resulting in health-related problems such as skin cancer
[121], cataracts [122], eye damage [123], aging [124], tanning of the skin [125],
damage to the cornea [126], to name a few. Hence, there is a pressing need to protect humans from radiation-induced waves (EM and UV rays) for which this section
discusses the nanostructured fabrics including protective finishing against the same.
4.3 Electromagnetic Waves
“Electromagnetic radiation is a form of energy that propagates as both electric and
magnetic waves and travelling in packets of energy called photons” [127]. Electromagnetic emission comprises of a wide spectrum of wavelengths that includes
infrared, ultraviolet, radio waves, microwaves, X-rays and gamma rays, which in turn
impacts severe physical damage, changes in the nerve cell performance and stimulating nerves and muscles. In this context, we are in a situation to protect ourselves
from these hazards and the same can be achieved by “shielding”. Through shielding,
one can reduce the exposure of high intensity electromagnetic waves by blocking
them with using conductive materials, magnetic materials and nanocomposites as
barriers.
Electromagnetic Waves Shielding Mechanism
When an electromagnetic wave propagates through a body, it could interact in three
different phenomena based on its strength.
1. Attenuated absorption
2. Attenuation due to reflection
3. Attenuation due to successive internal reflections.
Usually, the blocking mechanism in electromagnetic shielding is based on two
significant functions, namely, reflection phenomena by the conductive medium and
absorption phenomena in the volume of conductive surface.
When an electromagnetic wave strikes the conductive surface, it encounters two
types of losses, namely reflection and absorption [128, 129]. A few portions of the
waves get reflected while the remaining waves get transmitted. These waves also
gets attenuated when they pass through the conductive surface, which is depicted in
Fig. 12 [130]. This combined loss will determine the shielding effectiveness. Though
the barrier causes the absorption phenomena, the absorbed electromagnetic energy
can be converted into thermal energy. In general, shielding of EM waves can be
classified into two groups based on its material classification: