Nanofibres have a variety of applications in face masks, water filtration and cigarette filters, says Pradeep Kulshrestha.

Nanotechnology was conceived in Southern California in 1959, when Nobel laureate physicist Richard Feynman gave his now-famous lecture at California Institute of Technology, Pasadena. It was put forward in 1974 by Japanese Scientist Norio Taniguchi, who described machining in the range of 0.1 to 100 nanometers (nm).

Use of nanotechnology-based ultra-fine fibres and functional finishes in enhancing performance in textiles is growing fast. These are aimed at imparting antibacterial, moisture control, UV-resistant, water-repelling and wrinkle-resistant properties. Research is also under way to use nanotechnology for protection, hygiene and health.

Nanofibres are fibres with diameters in the 50-100 nm range with large specific surface area, high porosity and small pore size. These can be used to prepare filters for viruses and bacteria in face masks, tar and nicotine filters in cigarettes, to reduce release of solid particulate matter (SPM) into the environment and to produce energy-efficient water purifiers.

Ahmedabad Textile Industry's Research Association (ATIRA) has developed a nanofibre-based mask, which it claims, filters 99.9 per cent of H1N1 virus. The nanofibre has a micrometre-thick coating of nonwoven material that does not affect air flow or increase the weight of the mask. Rather, it significantly improves the mask's protective properties. A network of fibres of about 100 nanometres in diameter and about 1000 times thinner than a human hair offered a larger surface area of the face mask. The nanofibres contain silver nano particles about 50 nanometres in diameter that are capable of even killing viruses. For face masks, either single or a combination of nanofibre layers on a substrate is used as the middle layer between the spun-bonded nonwoven layers.

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Nanofibres are also used to prepare filters for cigarette smoke without affecting the pleasure of smoking. Additional filter discs made of nanoweb to filter harmful contaminants are attached externally to the cigarette filter.

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Nanofibre-based energy efficient membranes are a new breed of membranes with advantages like better energy efficiency and higher throughput. A nanofiltration (NF) membrane can be placed between the steps of ultrafiltration and reverse osmosis. Nano silver particles are added to impart anti-microbial properties to nanofibre layers. Nano silver particles in fibres help inhibit growth of odour-causing bacteria and fungus and are increasingly finding application in the personal and home hygiene sector.

Applications of nano technology

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About the author

Pradeep Kulshrestha is a textiles operations management expert. He is currently with Nandan Denim Limited (Chiripal Group), Ahmedabad as DGM, denim & shirting.