People do not have time to clean their daily clothes nowadays. Nanotechnology provides a new concept of self-cleaning textiles which gives self-cleaning as well as fresh cloths every day, this not only technically benefited but techno economically also benefited.
Nanotechnology has real commercial potential for the textile industry. This is mainly due to the fact that conventional methods used to impart different properties to Fabrics often do not lead to permanent effects, and will lose their functions after Laundering or wearing.
Manufacturing Method:
The self-cleaning textiles can be manufactured by application of either fluorocarbon or by nanotechnology.
Here are some of the nanotechnologies used to manufacture self-cleaning textiles
1.Using Photocatalyst 2.Using microwaves 3.Using carbon nanotubes 4.Using Metal oxide colloidal 5.Using silver nanoparticles
Using Photocatalyst
In this process Nano-sized, Titanium dioxide, and zinc oxide are used for imparting self-cleaning and anti-bacterial properties. Nano-crystalline titanium dioxide sols were prepared by hydrolysis and condensation reaction of 97% titanium tetra-isopropoxide in an acidic aqueous solution (pH 1) of glacial acetic acid and 37% hydrochloric acid wherein the concentration of titanium dioxide (TiO2) precursor varied. The composites were heated at 60°C under vigorous stirring for 2 hours. It is found that the intrinsic low-stress mechanical properties of fabrics change after the self-cleaning coating treatment. The tensile extensibility of coated fabrics decreases and the surface roughness increases.
The fabric is coated with a thin layer of titanium dioxide particles heaving 20 nanometers in diameter. Titanium dioxide is a photocatalyst when it is illuminated by the light of energy higher than its bandgap, electrons in TiO2 will jump from the valence band to the conduction band, and the electron (e-) and electric hole (h+) pairs will form on the surface of the photocatalyst. The negative electrons and oxygen will combine to form O2, radical ions, whereas the positive electric holes and water will generate hydroxyl radicals OH. Since both products are unstable chemical entities, when the organic compound falls on the surface of the photocatalyst it will combine with O2′ and OH’ and turn into carbon dioxide (CO2) and water (H2 O). Zinc oxide is also a photocatalyst, and the photocatalysis mechanism is similar to that of titanium dioxide.
Using microwaves
A new technology developed, which makes it possible to attach nanoparticles to clothing fibres by use of microwaves. So chemicals that can repel water, oil, and bacteria are directly bound to the nanoparticles. These two elements combine to create a protective coating on the fibres. This coating both kills bacteria and forces liquids to bead and runoff. The same technology, created by scientists working for the U.S. Air Force, has already been used to create t-shirts and underwear that can be worn hygienically for weeks without washing.
Using carbon nanotubes
Artificial lotus leaf structures were fabricated on textiles via the controlled assembly of carbon nanotubes. Carbon nanotubes (CNTs) and surface-modified carbon nanotubes are used as building blocks to mimic the surface microstructures of lotus leaves at the nanoscale. Cotton fabrics, which otherwise have perfect water absorption; have been endowed with superhydrophobic properties. Afterward, the water contact angle was increased and found greater than 150 degrees.
Using Metal oxide colloidal
The fabric is dipped and processed in metal oxide colloidal solution and then it is given heat treatment. Due to that fabrics get surface roughness on the nanometer scale. After that through water repellent treatment, the fabrics have a surface with a water contact angle above 1500.
Using Silver nanoparticles
Water repellent coating of silver nanoparticles offers superior resistance to dirt as well as water and requires much less cleaning than conventional fabrics. Nano-Tex improves the water-repellent property of fabrics by creating nanowhiskers, which are made of hydrocarbons and have about 1/1000 of the size of typical cotton fiber. They are added to the fabric to create a peach fuzz effect without lowering the strength of cotton.
Bottom line
The realization of self-cleaning properties on textile surfaces by using nanotechnology includes a vast potential for the development of new materials or new products and applications for known materials. The opening of new application fields for textiles will lead to a new growth stage. For the growing market of technical textiles a further increase in production volume, sales and application fields can be expected by successful transfer of the self-cleaning effect on textile materials. Structure-based soil and water-repellent properties lead to efficient use of materials and are therefore in agreement with the principles of sustainable development.
Textile Insights 