NanoFibres: Electro spinning is the process for nanofibres fabrication, which has patents extending back to the early and mid-1900s. In the process, electrostatic forces are used to draw a solution or melt polymer fluid into a fibrous form. Depending on the materials system and processing conditions, resulting fibres can range from several microns to less than 100 nanometres. Fibers used in the textile industry are notably improved by nanotechnology; one example is nanocellulose, which combines low cost, lightweight, electric conductivity, environmentally friendly resources and high resistance, thus opening an immensely vast scope of possible applications, nanotechnology-enabled apparel can both protect the wearer from pathogens, toxic gases, and other hazardous substances, benefiting the medical and rescue services as well as in the military, and allow the constant monitoring of body functions in applications ranging from regenerative activities to the enhancement of the quality of life of sufferers of long-term diseases.
Often the first application of nanotechnology to textiles that comes to the minds is related to nanofibers. Nanofibers are normally produced by the electrospinning process. The polymer must previously be dissolved in a solvent. The process makes use of electrostatic and mechanical forces to spin fibers from the tip of a fine orifice or spinneret, with evaporation of the solvent. This process produces in fact a nonwoven web and nanofibers normally cannot be used in common textile processing. Nanofibers have applications in medicine, including artificial organ components, tissue engineering, implant material, wound dressing and drug delivery. In fact, all these products are not normally considered as textile products, as they do not fully enter in the definition of the EU Regulation 1007/2011 (they cannot be processed like traditional fibres) and they are not normally present in general consumer products. This paper will not further consider nanofibers. In this paper we will also not include the use of carbon nanotubes.
In fact, carbon nanotubes pose serious health problems but, due to the present high cost, are for the moment only used in high-tech products and not in “normal” textile products. When we speak about “nanotextiles” we refer normally to traditional textile products in which engineered nanomaterials (normally nanoparticles) are incorporated or on which a nanostructured surface has been applied. In fact, nanotechnology is already very often used in textile products and involves the incorporation of nanoparticles in textile materials or the nanostructuration of the surface, in order to obtain specific functionalities . The most common effects are: water and dirt repellency (including self-cleaning properties, also called “lotus leaf” effect), antibacterial properties, protection against ultraviolet radiation and flame retardancy.
Table 1. Nanomaterials used in the functionalization of textiles
| Nanomaterial | Function |
| Silver (Ag) | antibacterial (odour), electrically conductive |
| Titanium dioxide(TiO2) | UV protection self-cleaning water and dirt repellent |
| Zinc oxide | UV protection antibacterial self-cleaning abrasion resistance, stiffness |
| Silicon dioxide (SiO2) | water and dirt repellent abrasion-resistant, reinforcement improved dyeability |
| Aluminium oxide (Al2O3) | abrasion resistance flame retardant |
| Nanoclays (e.g. montmorillonite) | abrasion resistance flame retardant support of active ingredients |
During fiber manufacturing, nanoparticles can be introduced by mixing in the polymer, before fiber spinning. The nanoparticles are evenly distributed inside the fiber volume. We can speak in this case of a “nanocomposite” material. The content of nanoparticles in the fiber can be as low as 0.1% to obtain a sufficient functionalization. When the incorporation is done by this process, the nanoparticles are firmly incorporated in the textile fiber and the effect is highly durable. The nanoparticles are inside the fiber and normally can only be released by means of abrasion. This fact poses low risk in terms of safety and health both for the workers involved in the subsequent textile processing and for the consumers.[2]
[2]: IOP Conf. Series: Materials Science and Engineering 254 (2017) 102002 doi:10.1088/1757-899X/254/10/102002