Nanofibre and submicron fibre web formation

For many decades, it has been possible to manufacture nonwovens from microfibres (<1 dtex) for reasons as diverse as mimicking the properties of leather and suede, modulating fabric softness and filtering submicron particles, amongst many others. As fibre science and manufacturing processes for making even smaller diameter fibres have advanced, the variety of nonwoven materials available containing submicron fibres have progressively grown, and developments in nanotechnology have had significant impact. Nanofibres can be considered as one branch of the nanomaterials tree. They combine a high aspect ratio and are of nanoscale diameter. Although the general definition of a nanomaterial covers a size range between 10 and 100nm, it is common for fibres with diameters up to 500nm to be referred to as nanofibres, while those in the range from 500 to 1000nm are usually described as submicron, i.e., <1μm [1]. The ability to make nonwovens continuously from nanofibres with diameters that may be 100,000 times smaller than a human hair is the result of progressive developments in polymer, spinning and nonwoven production techniques. This chapter reviews the key technologies and applications of nonwovens made from nanomicron- and submicron-diameter fibres.