Self-Cleaning Cloths Based on Nano Technology
Department of Textile Engineering
World University of Bangladesh
Since long days scholars are trying to make cloths clean without any soaping agent, after long research scientists have got the charming result about this matter. By using Nanotechnology and multifunctional chemical finish it is possible to make self-cleaning cloths. The aim of this paper is to show the mechanism of self-cleaning cloths with a technical approach.
Keyword: Nanotechnology, Self-clean, lotus- leaves, hydrophobic, adhesion, Bacteria
We have got a wonderful substance from our nature, which is specially acted as a self-cleaning substance. This is the lotus leaves. “Lotus leaves” is the best example of self-cleaning surfaces. The technology of self-cleaning coatings has developed rapidly in recent years. As a commercial product, their potential is huge and their market truly global. Because of the wide range of possible applications. The concept of self-cleaning textiles is based on the lotus plant whose leaves are well-known for their ability to ‘self-clean’ by repelling water and dirt. Water and soil repellency has been one of the major targets for fiber and textile scientists and manufacturers for centuries. Nano science is employed for this type of problems. From the Nano science self-cleaning is the wonderful technology for dirt free with other functional finishes.
What is self-cleaning cloth?
Cleaning clothes usually requires soap and water to remove stains and smells, and a tumble in the dryer or an afternoon on the clothesline to dry. The time and energy needed to turn a heap of dirty laundry into a pile of clean clothes might make people wish for clothes that just clean themselves. That wish is a step closer to coming true. Recent experiments show that cotton fabric coated with the right mixture of chemicals can dissolve stains and remove odors after only a few hours in the sun.
Nano Technology defined as “the deliberate and controlled manipulation, precision placement, measurement, modeling and production of matter at the Nano scale in order to create materials, devices and systems with fundamentally new properties and functions”
According to US Foresight Institute “Nanotechnology is a group of emerging technologies in which the structure of matter is controlled at the nanometer scale to produce novel materials and devices that have useful and unique properties”
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 nanometers (1 Billion Nanometers = 1 Meter), although 100 nanometers presently is the practically attainable dimension for textile products and applications. 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. Nanotechnology can provide high durability for fabrics, because Nano-particles have a large surface area-to-volume ratio and high surface energy.
Self- cleaning Mechanism
Nanocare fabrics are created by modifying the cylindrical structure of the cotton fibres making the fabric. At the nanoscale, cotton fibres 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 droplet on an inclined super hydrophobic surface does not slide off; it rolls off. When the droplet rolls over a contamination, the particle is removed from the surface if the force of absorption of the particle is higher than the static friction force between the particle and the surface. Usually the force needed to remove a particle is very low due to the minimized contact area between the particle and the surface. As a result, the droplet cleans the leaf by rolling off the surface.
Due to their high surface tension water droplets tend to minimize their surface trying to achieve a spherical shape. On contact with a surface, adhesion forces result in wetting of the surface: either complete or incomplete wetting may occur depending on the structure of the surface and the fluid tension of the droplet. The cause of self-cleaning properties is the hydrophobic water- repellent double structure of the surface. This enables the contact area and the adhesion force between surface and droplet to be significantly reduced resulting in a self-cleaning process.
2-anthraquinone carboxylic acid (2-AQC) used into fabrics. The chemical bonds become very sturdily to the cellulose in the cotton, which makes it very hard to wash off. When it’s exposed to light, the 2-AQC produces “reactive oxygen species” like hydrogen peroxide that kills bacteria and can also break down other toxic chemicals like pesticides.
Key Features of self-cleaning cloths
- Superior Stain, Water and Oil Repellency
- Resists Wrinkles
- Breathable Fabric & Easy Care
The realization of self-cleaning properties on textile surfaces by using the 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.
- www.fibre2fashion.com\technical textile\self-cleaning finishing
- http://www.lotusan.de/ (in German).
- A. Marmur, Langmuir, 2004, 20, 3517. 15