Modern Applications Of Nanotechnology in Textile Finishing

ABSTRACT:

Today the use of nanotechnology is allowing textiles to become multifunctional. The emergence of a reality to create, alter and improve textiles at the molecular level, and to enhance their durability and performance beyond those of existing textile products, is already apparent due to applications of nanotechnology. Most often, nanomaterials are impregnated onto textile materials without significantly affecting their texture or comfort. At present, antibacterial and UV-resistance are the major functional properties under examination for nanofinished textiles. An additional benefit to using metal nanoparticles is the presence of surface plasmons that impart different colors by varying their size and shape. Nanotechnology provides a means of adding value to the textile product, and may in future represent a valuable tool for generating extra revenue in the hard-pressed textile industry

Characteristics of Nano Finishing in garments:

1.      Nano-processed garments have protective coating, which is water and beverage repellent.

2.      Their protective layer is difficult to detect with the naked eye.

3.      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.

4.      Saving time and laundering cost.

5.      This technology embraces environmental friendly properties.

6.      Nano-materials allow good ventilation and reduce moisture absorption, resulting in enhanced breathability while maintaining the good hand feel of ordinary material.

7.      The crease resistant feature keeps clothing neat.

8.      Nano-processed products are toxic free.

9.      Garments stay bright, fresh looking and are more durable than ordinary materials.

10. Manufacturing cost is low, adding value to the products.

Some commercially available nano-particles:

Nano-particles may consist of various elements and compounds. The size of the molecules is the sole criterion for inclusion in the category of nano-particles. Nano-of 1 to 100 nm. Conventional materials have grain sizes ranging from microns to several millimeters and contain several billions atoms each, nanometre sized grains contain only about 900 atoms, exhibit new and improved properties compared to the corresponding bulk material. Some nano-particles currently available are as follows :

1.      Metals: Pd/Pt, Ag, Fe, etc.

2.      Compounds: – Organic: Vitamins, DNA, Hydroxylapatite, Colour pigments.
- Inorganic: TiO2, ZnO, Fe2O3, MgO, SiO2 etc.

3.      Polymer  – cellulose nano-whiskers
- carbon nano-whiskers.

Sr. No	Nano-Particles	Properties
1	Silver Nano-Particles	Anti-bacterial finishing
2	Fe Nano-Particles	Conductive magnetic properties, remote heating.
3	ZnO and TiO2	UV protection, fiber protection, oxidative catalysis
4	TiO2 and MgO	Chemical and biological protective performance, provide self-sterilizing function.
5	SiO2 or Al2O3 Nano-particles with PP or PE coating	Super water repellent finishing.
6	Indium-tin oxide Nano-Particles	EM / IR protective clothing.
7	Ceramic Nano-Particles	Increasing resistance to abrasion.
8	Carbon black Nano-Particles	Increasing resistance to abrasion, chemical resistance and impart electrical conductivity, colouration of some textiles.
9	Clay nano-particles	High electrical, heat and chemical resistance.
10	Cellulose Nano-whiskers	Wrinkle resistance, stain resistance, and water repellency.

                  Table: Nano-particles and potential textile applications

Nanotechnology 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.

Self-cleaning Fabrics:

A self-cleaning cotton fabric known as nano-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 nano scale, cotton fibres look like tree trunks. Using  nano techniques, 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.

Antimicrobial finish :

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 recognized. 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:

The most 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 .
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 UV-blocking property.

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.

Nano technology for wrinkle free treatment:

Nano-Tex has launched a new nanotechnology-based wrinkle-free treatment that is said to offer an improved performance while preserving fabric strength and integrity – providing an alternative to harsh traditional processes.

chemicals and processing methods reduce a fabric’s tear and tensile strength. This means there are certain fabrics and garments that are Wrinkle-free textiles are popular and convenient for time-pressed consumers, but traditional not candidates for wrinkle-free technology, such as lightweight fabrics or slim fitting garments. Sometimes fabrics also need to be over-engineered or “beefed up” in order to withstand the fibre degradation caused by traditional wrinkle-free solutions. Either way, current technologies either do not work on all fabrics – or the brand/retailer has to incur additional expense just to accommodate the destructive properties of wrinkle-free chemistry.

The nano-scale molecular structure in Nano-Tex’s new Fortify DP technology penetrates more deeply in the fibre to improve wrinkle-free performance. Additionally, it uses a longer and more flexible cross-linking chain which reduces fibre stress under tension, thus reducing the significant strength loss associated with traditional wrinkle-free chemistry.

Economical and environmental aspects:

The unique properties of nanomaterials have attracted not only scientists and research workers but also businesses, because of their huge economic potential. The national science foundation reports that nano-related goods and services will increase to a US$ 1 trillion market by 2015. This amount is larger than the combined businesses of the telecommunications and information technology industries. Several hundred billion Euros are forecast to be created by nanotechnology in the next decade ⁽²⁴⁾. The nano materials markets could expand to US$ 4 billion by 2007. It was believed that 2 million new employment opportunities would be created in order to meet the worldwide annual production demand of US$ 1 trillion in 10-15 years.

Nanotechnology may impart favourably on the environment as well. By using less resource without sacrificing performance, nanotechnology may save raw materials and also upgrade quality of life.

Conclusion:

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 applications.

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 odor-less undergarments.