Nanotechnology is an umbrella term
covering a wide range of technologies concerned with structures and
processes on the nanometre scale. Because of its potential to change
fundamentally whole fields of technology, nanotechnology is regarded as a
key technology, which will not only influence technological development in
the near future, but will also have economic, social and ecological
implications. Nanotechnology deals with the science and technology at
dimensions of roughly 1 to 100 nanometres (1 Billion Nanometres = 1 Metre),
although 100 nanometres presently is the practically attainable dimension
for textile products and applications (2).
The technology can be used in engineering desired textile attributes, such
as fabric softness, durability, and breath ability and in developing
advanced performance characteristics, namely, water repellency, fire
retardancy, antimicrobial resistance, etc in fibres, yarns and fabrics (1).
Enhancement of textile materials by nanotechnology is expected to become a
trillion dollar industry in the next decade, with tremendous technological,
economic and ecologic benefits. It was estimated that for the year 2003, the
worldwide government funding for the research and development in the area of
nanotechnology had increased to $3 billion annually in addition to the
millions of dollars invested by private industries (3). Although, textile
industry is a small part of the global research in the emerging areas of
nano-technology, the fibres and textiles industries in fact were the first
to have successfully implemented these advances and demonstrated the
applications of nanotechnology for consumer usage.
With the advent of nano
technology, a new area has developed in the realm of textile finishing. Nan
coating the surface of textiles, clothing, and textiles for footwear is one
approach to the production of highly active surfaces to have UV-blocking,
antimicrobial and self-cleaning properties. The self-cleaning property can
be imparted by nano-TiO2/nano-ZnO coating (6).
From functional to
intelligent and smart textiles
Intelligent clothing is articles of clothing,
footwear or accessories that feature microelectronic sensors. Smart clothes
are the combination of intelligent and fashionable clothing. The required
thermal insulation of clothing system depends on the physical activity and
on the surrounding conditions. The quantity of heat produced by the body
depends very much on the physical activity and can vary from 100W while
resting to over 1000W during maximum activity. During the cooler seasons
approximately 0ºC, the recommended thermal insulation is defined in order
to ensure that the body is sufficiently warm when resting (22).
At a more
intensive activity, this is the case with sportsmen, the body temperature
increases with enhanced heat production. To keep this increase within a
certain limit, the body perspires in order to withdraw energy from the body
by evaporative cooling. Intelligent textiles used to improve insulation are
the phase change materials and the shape memory materials. The other main
application of intelligent materials is the fashion field, to create fantasy
design thanks to the chromic materials. Some examples of these are: Music
T-Shirts, business garments, solar energy recharge jacket, and etc.
Integration of electronic technology into clothing means the start of a
whole new era in the fashion industry.
Existing functional materials on the
market are waterproof, windproof with good breath-ability and moisture
transport. They possess optimised material properties like colour fastness,
tear and rubbing strength, heat and cold resistance etc. New on the market
are odour release or odour prevention, individually adjustable heat
insulation, microcapsules and phase change materials, protection from
environmental stress like UV radiation, etc. The textile industry is already
impacted by nanotechnology. These research endeavours are mainly focused on
using nano size substances and generating nanostructures during
manufacturing and finishing processes.
Application of nano fibres in
Nonwoven fabrics composed of nanofibres have a large
specific-surface area and small pore size as compared to commercial textiles
making such nonwoven materials excellent candidates for filter and membrane
applications. Although electro-spinning is inherently a chaotic process
producing non-woven fibre mesh, it is possible to fabricate mesh with
varying degrees of fibre alignment. Given the flexibility and versatility of
the electro-spinning process in future mass production of the fibres through
eco-friendly systems is foreseen.
Concurrent research in nanofibre
application and process optimisation, electro-spinning will become the
dominant production process for Nanofibres and associated meshes, which will
yield to major breakthroughs in this century. The recent outbreak of
pandemics such as SARS and the looming threat of Avian Flu, demand high
levels of public health protection. The risk of infection is typically high
among healthcare workers. There is a need for protective systems, which can
safeguard the wearer from a possible chemical or biological hazard in the
As such it is necessary to develop a highly sensitive
nanocomposite interface for the detoxification and detection of chemical
agents and biological toxins. Polymer nanofibres have an already proven
capability in molecular-level detection, and are best suited for breathable
fabric designs. Conducting nano fibres are the best materials for gas
sensing and biosensor applications. It is necessary to fabricate
functionalised electro-spun nanocomposite fabrics that will destroy or
eliminate these toxins.
Nanocomposites provide a high porosity where the
high surface area and the nature of the active nano material selected will
absorb and decompose chemical and biological agents into harmless products.
Conjugated polymers having specific reactive functional groups can be used
as sensing interfaces.
Nanotechnology in textile finishing
What is sol-gel processing?
It is a
process for making very small particles 20 to 40nm that are virtually
impossible to make by conventional grinding. Its main use at present seems
to be for optical coatings where the finer particles give better optical
clarity. Manufacture of fine a ceramic fibre seems to be the other common
How does sol-gel processing work?
A liquid precursor of the
particle is dissolved in a solvent, usually alcohol, water is added and then
acid or base. The mixture is coated or cast. The precursor then decomposes
to form the fine ceramic particles. If the particle concentration is high
enough, the mixture gels. The gel is dried, and then heated at high
temperature to sinter the ceramic, giving the desired ceramic film or fibre.
During this drying and sintering process, shrinkage occurs through loss of
solvent and air, and this shrinkage must be carefully controlled to avoid
The German researcher Wilhelm Barthlott of the Bonn Institute of
botany discovered, in 1990, that the lotus plant, admired for the
resplendence of its flowers and leaves, owed this property of self-cleaning
to the high density of minute surface protrusions. These protrusions catch
deposits of soil preventing them from sticking.
When it rains, the leaf has
a hydrophobic reaction. Water rolls around as droplets, removing dust as it
moves. Reproduced for nano technological process on the surface of woven
fabrics, this self-cleaning property can be developed as a technological
innovation. The fabric will have specific applications such as sails or
cotton fabric known as nanao-care was developed and is marketed by an
American Company, Nanotex and stain-resistant jeans and khakis are available
since 1990. Nanocare fabrics are created by modifying the cylindrical
structure of the cotton fibres making up the fabric. At the nanoscale,
cotton fibres look like tree trunks. Using nanotechniques, these tree trunks
are covered in a fuzz of minute whiskers which creates a cushion of air
around the fibre. When water hits the fabric, it beads on the points of the
whiskers, the beads compress the air in the cavities between the whiskers
creating extra buoyancy. In technical terms, the fabric has been rendered
super-non wettable or super-hydrophobic. The whiskers also create fewer
points of contact for dirt. When water is applied to soiled fabric, the dirt
adheres to the water far better than it adheres to the textile surface and
is carried off with the water as it beads up and rolls off the surface of
the fabric. Thus the concept of "Soil-cleaning" is based on the
leaves of the lotus plant.
It is a well-known fact that
the growth of bacteria and microorganisms in food or water is prevented when
stored in silver vessels due to its antibacterial properties. The
anti-bacterial properties of silver are now scientifically recognised.
Silver ions have broad spectrum of anti microbial activities. The method of
producing durable silver containing antimicrobial finish is to encapsulate
silver compound or nano particle with a fibre reactive polymer like poly
(styrene co-maleic anhydride)
UV protective finish
important functions performed by the garment are to protect the wearer from
the weather. However it is also to protect the wearer from harmful rays of
the sun. The rays in the wavelength region of 150 to 400 nm are known as
ultraviolet radiations. The UV-blocking property of a fabric is enhanced
when a dye, pigment, delustrant, or ultraviolet absorber finish is present
that absorbs ultraviolet radiation and blocks its transmission through a
fabric to the skin (5).
Metal oxides like ZnO as UV-blocker are more stable
when compared to organic UV-blocking agents. Hence, nano ZnO will really
enhance the UV-blocking property due to their increase surface area and
intense absorption in the UV region. For antibacterial finishing, ZnO
nanoparticles scores over nano-silver in cost-effectiveness, whiteness, and
Fabric treated with UV
absorbers ensures that the clothes deflect the Harmful ultraviolet rays of
the sun, reducing a persons UVR exposure and protecting the skin from
potential damage. The extent of skin protection required by different types
of human skin depends on UV radiation intensity & distribution in
reference to geographical location, time of day, and season. This protection
is expressed as SPF (Sun Protection Factor), higher the SPF Value better is
the protection against UV radiation (12).
Characteristics of nano finishing
Nano-processed garments have protective coating, which is
water and beverage repellent.
Their protective layer is difficult to
detect with the naked eye.
When a substance is manipulated at sizes of
approximately 100 nm, the structure of the processed clothing becomes more
compressed. This makes clothing stain- and dirt-resistant.
and laundering cost.
This technology embraces environmental friendly
Nano-materials allow good ventilation and reduce moisture
absorption, resulting in enhanced breathability while maintaining the good
hand feel of ordinary material.
The crease resistant feature keeps
Nano-processed products are toxic free.
bright, fresh looking and are more durable than ordinary materials.
Manufacturing cost is low, adding value to the products.
applications in textiles
Due to the advancement of nano-technology in the
manufacturing of fibres/yarns as well as in the development of fabric
finishes, the applications and scope of nanotechnology in the area of
textiles are widespread (14).
There is a significant potential for profitable
applications of Nano-technology in cotton and other textiles. Several
applications of Nano-technology can be extended to attain the performance
enhancement of textile manufacturing machines & processes. In future,
interdisciplinary research collaborations will lead to significant
advancements in the desirable attributes of cotton and cotton blend textile
The textile industry has the biggest customer base in the
world. Therefore, advances in the customer-oriented products should be the
focus for the future nanotechnology applications. The future research should
be targeted on developing improved dirt, crease and shrink resistance
properties in fabrics, temperature adaptable clothing and odour-less
Future Needs and Challenges for Materials and
Nanotechnology Research, European Commission Research Directorate General.
Textiles Intelligence (www.textilesintelligence.com)
Nanotechnology, January 2004
Nanotechnology Sees Payoff in Consumer
Markets - www.centredaily.com
Functional textiles - www.empa.ch
Qian L and Hinestroza J P:
Application of Nanotechnology for High Performance Textiles, Journal of
Textile and apparel, Technology and Management, 2004, Vol 4.
S S: Applications of Nanotechnology in Fibre Finishing, Synthetic Fibres,
2003. 32: pp 20-22.
Xin J H, Daoud W A and Kong Y Y: A New Approach to
UV-Blocking Treatment for Cotton Fabrics, Textile Research Journal, 2004.
74: pp 97-100.
Anonymous, Nanotechnologies Keep Feet Healthy, Advance in
Textiles Technology, 2003. 3: pp 10-11.
S Pervez Abbas: Nanotechnology
& Textile Finishing Workshop.
Aung Kyaw Soe, Masoki takahashi:
Structure and Properties of MVS Yarns in Comparison with Ring and OE Yarns,
Textile Research Journal, Sep 2004.
Huseyin Gazi Ortlek, Sukriye Ulku:
Effect of Some Variables on Properties of 100% Cotton Vortex Spun Yarn,
Textile Research Journal, June 2005.
Smart Textiles and Nanotechnology;
The News Service for Textile Futures, Issue 1, Nov 2006.
and Nanotechnology; The News Service for Textile Futures, Issue 2, Nov 2006.
Chidambaram Rameshkumar: Application of Nano Technology, Technical
Textiles, Textile Magazine, Aug 2000.
P B Jhala: Nanotechnology in
Textiles; Indian Textile Journal, May 2004.
T Ramachandran, K
Rajendrakumar and R Rajendran: Antimicrobial Textiles - Overview; IE (I)
Journal, Feb 2004.
Arun Naik, Nanotechnology Applications in Textiles:
International Conference on "Advances in Textiles Machinery, Nonwoven
and Technical Textiles", June 2007.
Note: For detailed version of this
article please refer the print version of The Indian Textile Journal January
Department Of Textile Technology,
College of Technology,
Coimbatore 641 006.