28
D. K. Subbiah et al.
of the promising candidates for the protection of electromagnetic waves owing to its
higher stability and conductivity. However, these materials possess few drawbacks
such as high cost and their immediate ability to get oxidized or undergo corrosion
under ambient conditions. In this context, development of wearable EM protective
suits by modifying the surface of fabrics with nanomaterials has gained significant
momentum to produce protective textiles against EM waves.
4.4 Ultraviolet Protection Fabrics
Prolonged exposure of ultraviolet (UV) radiation from the sun has been identified as
the cause for several adverse human related effects such as skin cancer, eye damage,
cataracts, wrinkles, sunburn, tanning, suppression of immune system and genetic
damage to cells [137–139]. The Occupational Safety and Health Administration
(OSHA) suggested the prevention of UV rays by covering up the skin with woven
fabrics & hat, sunscreen lotions and UV absorbent materials [20]. Though, the sunscreen lotions and absorbents [140] play a crucial role in blocking the skin from these
harmful rays, many of the sunscreen lotions are toxic, unstable and are moderately
effective against UV-A region rays [141]. In the last few decades, literature relating
to blocking of UV radiations by altering the physical parameters of the fabrics, i.e.,
fiber type, dyes, fabric porosity between warp and weft count and thickness has been
increasing. As a consequence, researchers and scientists have started exploring multifunctional structures by modifying the surface of fabrics with such UV absorbing
materials. These materials could be prepared by different modification techniques
such as chemical bath technique, padding, sputtering, printing and solution growth
process to satisfy the UV protection property of the material.
In this context, inorganic materials have been utilized for the development of multifunctional fabrics owing to the ease at which their properties could be tuned. Among
the materials used in UV blocking fabrics, TiO 2 [142] and ZnO [20] were found to
possess excellent UV blocking characteristics along with antibacterial property due to
their photocatalytic behaviour. Generally, nanoparticles exhibit unique physical and
chemical characteristics due to their large surface to volume ratio, which can absorb
and scatter UV light. More recently, researchers have started focusing on exploring
metal oxide materials, which could perform as a UV blocker even in the visible region
by altering the bandgap. Also, metal oxide materials possess the combination of electronic structure alteration, charge transport behaviour, light absorption properties and
excited lifetimes. From this background, incorporation of metal oxide materials on
the surface of fabrics for UV protection fabrics is a viable and effective alternative.
For instance, ZnO modified fabrics are kept in ambient atmosphere, oxygen from the
atmosphere adsorb onto the surface where the electrons from the conduction band
of the material forms a depletion layer of O 2
− ions on the surface of the modified
fabrics. But under UV illumination, these fabrics could excite the photogenerated
electrons from the valence band (VB) to the conduction band (CB) and result in
D. K. Subbiah et al.
of the promising candidates for the protection of electromagnetic waves owing to its
higher stability and conductivity. However, these materials possess few drawbacks
such as high cost and their immediate ability to get oxidized or undergo corrosion
under ambient conditions. In this context, development of wearable EM protective
suits by modifying the surface of fabrics with nanomaterials has gained significant
momentum to produce protective textiles against EM waves.
4.4 Ultraviolet Protection Fabrics
Prolonged exposure of ultraviolet (UV) radiation from the sun has been identified as
the cause for several adverse human related effects such as skin cancer, eye damage,
cataracts, wrinkles, sunburn, tanning, suppression of immune system and genetic
damage to cells [137–139]. The Occupational Safety and Health Administration
(OSHA) suggested the prevention of UV rays by covering up the skin with woven
fabrics & hat, sunscreen lotions and UV absorbent materials [20]. Though, the sunscreen lotions and absorbents [140] play a crucial role in blocking the skin from these
harmful rays, many of the sunscreen lotions are toxic, unstable and are moderately
effective against UV-A region rays [141]. In the last few decades, literature relating
to blocking of UV radiations by altering the physical parameters of the fabrics, i.e.,
fiber type, dyes, fabric porosity between warp and weft count and thickness has been
increasing. As a consequence, researchers and scientists have started exploring multifunctional structures by modifying the surface of fabrics with such UV absorbing
materials. These materials could be prepared by different modification techniques
such as chemical bath technique, padding, sputtering, printing and solution growth
process to satisfy the UV protection property of the material.
In this context, inorganic materials have been utilized for the development of multifunctional fabrics owing to the ease at which their properties could be tuned. Among
the materials used in UV blocking fabrics, TiO 2 [142] and ZnO [20] were found to
possess excellent UV blocking characteristics along with antibacterial property due to
their photocatalytic behaviour. Generally, nanoparticles exhibit unique physical and
chemical characteristics due to their large surface to volume ratio, which can absorb
and scatter UV light. More recently, researchers have started focusing on exploring
metal oxide materials, which could perform as a UV blocker even in the visible region
by altering the bandgap. Also, metal oxide materials possess the combination of electronic structure alteration, charge transport behaviour, light absorption properties and
excited lifetimes. From this background, incorporation of metal oxide materials on
the surface of fabrics for UV protection fabrics is a viable and effective alternative.
For instance, ZnO modified fabrics are kept in ambient atmosphere, oxygen from the
atmosphere adsorb onto the surface where the electrons from the conduction band
of the material forms a depletion layer of O 2
− ions on the surface of the modified
fabrics. But under UV illumination, these fabrics could excite the photogenerated
electrons from the valence band (VB) to the conduction band (CB) and result in