The concept of clothing is under constant transformation through innovations in wearable technologies. A new revolution in this sector is in nano-engineered functional textiles, opening up vast possibilities for nano-based textiles, attracting researchers from different fields.
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Nano-based textiles were developed based on the increasing demand of the customers to have multifunctional wearable materials. Nanomaterials could provide many added functions to the fabric, such as stain repellence, wrinkle-resistant, anti-static properties, and electric conductivity to fibers without compromising the initial comfort.
Textile is considered as an ideal substrate for the incorporation of nanomaterials, in addition to the development of electronics and optical devices. Such nanomaterial integrated textiles could be developed for devices such as sensors, data transmitters, and processing units.
These nano-based textiles and fabrics are integrated into garments maintaining the intrinsic flexibility and comfort of the textile. There should be no allergic reaction to the body as well.
Applications of Nanotechnology in Textiles
Water repellent fabrics have been created by forming nanowhiskers made of hydrocarbon. This concept is adopted from nature’s lotus leaves, where the water droplet glides over the leaves without wetting them. The distance between the whiskers is such that it is smaller than the droplet size and larger than the size of water molecule, providing high surface tension for the water droplet.
Carbon nanotubes coated fabric mimicking structures in lotus leave were studied as hydrophobic fabrics. Other techniques explored to obtain water repellent fabrics have resulted in creating three-dimensional surface structures or by coating the textiles with nano-based films.
Oil repellent and hydrophobic fabrics were simultaneously implemented using silicon dioxide (SiO2) nanoparticles, surface treated with separate chemicals to induce hydrophobicity and oleophobicity.
In general, hydrophobic fabrics develop high static charges in the textile, whereas, the moisture content in the hydrophilic fabrics limits the development of static charges.
Titanium dioxide (TiO2), zinc oxide (ZnO), and doped tin oxide (SnO2) nanoparticles were explored to develop anti-static fabrics. These nanoparticles are electrically conductive, limiting the development of static charges.
Wrinkle-resistant fabrics have been reported with the incorporation of TiO2 nanoparticles with special coatings. These coated TiO2 nanoparticles develop crosslinking with cellulose molecules in cotton fabric, which prevents the creasing of fabric.
Nano-based textiles were further explored to enhance the strength of the fabric by using carbon nanotubes incorporated into polymer composite fibers.
Semiconducting nanoparticles are excellent absorbers and scatterers of light in the ultra-violet wavelength region. The size of these nanoparticles can be tuned to scatter light of different wavelength regions.
For example, TiO2 nanoparticles synthesized through sol-gel method, having size in the range of 20 to 40 nm, can scatter the light in the wavelength region of 200-400 nm. These nanoparticles incorporated textiles show a UV protection effect.
Nanomaterials with anti-bacterial properties like silver (Ag), TiO2, ZnO nanoparticles are utilized to develop anti-bacterial and anti-fungal properties to the textile. Ag nanoparticles are effective at slowing the growth of bacteria that cause body odor and itchiness. Application of Ag nanoparticles in socks was found effective in preventing bacterial and fungal growth.
Nasiol Hydrophobic Nano Coatings for Textile Surfaces
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Nano-based Textiles for Electronics
Nano-based textiles have shown enormous applications in electronic devices. Electrically conducting polymers like polypyrrole (PPy), polythiophene (PT) and polyaniline (PANI) were explored to develop sensors and actuators in the textile materials. Field-effect transistors in flexible logic circuits were reported to be developed through these conducting polymers.
Conductive textiles were developed through the incorporation of layered graphene in cotton fabric, as reported in a publication. The electrical conductivity was found enhanced by three orders of magnitude with the increase in the coating cycles of graphene over the fabric.
Nano-engineered textiles were also reported for several energy storage devices. Carbon nanotube and PANI composite textile were studied as flexible supercapacitor in a study. This supercapacitor was developed in combination with photovoltaic device to construct a self-powering fabric.
Yet another study reports nano-based textile for energy generation. Encapsulating carbon black nanoparticles in a thin layer of polymer showed harvesting electrostatic energy generated through contact and friction.
Yarn-based supercapacitors with the ability to restore the broken yarn electrode have been developed. The electrodes were fabricated by encapsulating the magnetic material in a polymer shell. The broken yarn could self-heal due to the magnetic attraction, and the polymer shell could regain the mechanical strength of the yarn.
Diode integrated textiles have applications in electronic circuitry. For example, Schottky diode integrated over materials involves the deposition of ZnO nanorods over Ag coated textiles.
Textiles that could sense temperature, humidity, and pressure have been investigated. Here, the sensor is created via photolithography and inkjet printing techniques. In another report, metal-organic framework created over quantum nanorods integrated cotton fabrics has shown applications in colorimetric sensors for the detection of toxic gases.
A study conducted at the University of Arkansas in the USA, has reported nano-engineered textile-based wearables indicating applications in the telemedicine sector. This technique allows monitoring of the physical body condition on a daily basis.
Are Nano-based Textiles Toxic?
The major challenge with nano-based textiles is that their usage cannot be as casual as that of other everyday materials. For instance, the release of nanoparticles while washing the garment has been reported. This release depends on the method of incorporation of nanomaterials into the fabric, washing procedure, and the detergent composition used for washing.
Considerable amounts of Ag nanoparticles were found to be released on washing Ag nanoparticle integrated fabrics, which is highly toxic to aquatic life.
The toxicity effect of nano-bases textiles against human health has not been studied in a broad perspective. Furthermore, the available data is debatable and depends on several parameters of the nanomaterial, which makes it incomparable.
Nano-based Textiles and the Future
As reported in many studies, there are countless nano-based textiles and fabrics applications, such as medicine, military, fashion/entertainment, sportswear, and many more.
The benefits of nano-based textiles and fabrics come with various risk factors. Proper public awareness about these textiles and the adequate broad assessment of their usage and disposal could help overcome the risk factors.
Continue reading: Nanofabrication: Techniques and Industrial Applications.
References and Further Reading
Yetisen, A.K., Qu, H., Manbachi, A., Butt, H., Dokmeci, M.R., Hinestroza, J.P., Skorobogatiy, M., Khademhosseini, A. and Yun, S.H. (2016) Nanotechnology in textiles. ACS nano, 10(3), pp.3042-3068. Available at: https://doi.org/10.1021/acsnano.5b08176
Syduzzaman, M.D., Patwary, S.U., Farhana, K. and Ahmed, S. (2015) Smart textiles and nano-technology: a general overview. J. Text. Sci. Eng, 5(1). Available at: http://dx.doi.org/10.4172/2165-8064.1000181
Saleem, H. and Zaidi, S.J. (2020) Sustainable Use of Nanomaterials in Textiles and Their Environmental Impact. Materials, 13(22), p.5134. Available at: https://doi.org/10.3390/ma13225134
Shateri-Khalilabad, M. and Yazdanshenas, M.E. (2013) Fabricating electroconductive cotton textiles using graphene. Carbohydrate polymers, 96(1), pp.190-195. Available at: https://doi.org/10.1016/j.carbpol.2013.03.052
Huang, Y., Huang, Y., Zhu, M., Meng, W., Pei, Z., Liu, C., Hu, H. and Zhi, C. (2015) Magnetic-assisted, self-healable, yarn-based supercapacitor. ACS nano, 9(6), pp.6242-6251. Available at: https://doi.org/10.1021/acsnano.5b01602.
Rai, P., Oh, S., Shyamkumar, P., Ramasamy, M., Harbaugh, R.E. and Varadan, V.K. (2013) Nano-bio-textile sensors with mobile wireless platform for wearable health monitoring of neurological and cardiovascular disorders. Journal of The Electrochemical Society, 161(2), p.B3116. Available at: https://doi.org/10.1149/2.012402jes