The definition of ‘Nano’ means it is one billionth of a meter. This size is equivalent to the size of three to four molecules. Generally, nanofibers are in the range of 100nm – 200nm and specifically in the textile industry, such definition is extended to include fibers up to 1000nm diameters. 1 gram of fiber with a diameter of 200nm can reach up to 300,000km in length, which is equivalent to 3/4 of the Earth’s circumference.
Nano membrane is a 3 dimensional network composed of stacked web of nanofibers. Such nanofibers coatings and nano membranes are produced through proprietary electrospinning process using various polymers. The interconnected and porous nanofibers have enormous surface area for its volume and has shape of a mesh.
Due to these unique features, it is very thin and light weighted. It also has high penetrability and permeability, but is also effective at resisting liquid and wind. These properties are particularly advantageous for high efficiency filter materials, energy storage materials, tissue engineering, biomedical application, micro-electronic mechanical system materials, nano complex materials and other applications.
Further, by applying nano membrane to regular textile, it enhances functionality to be used as technical textiles in various application.
Materials in fiber form are of great practical and fundamental importance. The combination of high specific surface area, flexibility and superior directional strength makes fibers a preferred material form for many applications ranging from clothing to reinforcements for aerospace structures. Although the effect of fiber diameter on the performance and processability of fibrous structures have long been recognized, the practical generation of fibers down to the nanometer scale was not realized until the rediscovery and popularization of the electrospinning technology over a decade ago.
The ability to create nanoscale fibers from a broad range of polymeric materials in a relatively simple manner coupled with the rapid growth of nanotechnology in the recent years have greatly accelerated the growth of nanofiber technology.
Human hair compared to Nanofiber
Current Nanofiber Restrictions
Current nanofiber production methods are highly inefficient and prohibitively costly.
Methods such as electro‐spinning, melt‐blown or other processes can only produce nanofibers in small amounts and at high cost.
Additionally, current methods require the use of highly toxic organic solvents, which are harmful to the environment and difficult to remove from the finished fibers, limiting their use in many areas, notably in the bio‐medical fields.
Current nanofibers are also produced from petroleum and are not biodegradable further limiting their use.
Current Nanofiber Fabrication Techniques
There are several methods for producing small diameter fibers using high-volume production methods, such as flash-spinning, island-in-sea, and melt-blowing. However, the usefulness of the above methods is restricted by combinations of narrow material ranges, high costs and difficulty in producing nanofibers.
At present, only a few processing techniques can successfully produce fibers, and subsequent scaffolds, on the nanoscale. The limitations encountered in the production of nanofibers include the low productivity of current fiber-spinning techniques and the concern over toxic residues due to the unavoidable use of organic solvents.
These concerns are especially problematic in rapidly growing life sciences applications such as advanced wound dressings, tissue engineering and drug delivery.
Nanofibers in Life Sciences
Fibrous materials at the nanometer scale are the fundamental building blocks of living systems.
From the 1.5 nm double helix strand of DNA molecules, including cytoskeleton filaments with diameters around 30 nm, to sensory cells such as hair cells and rod cells of the eyes, nanoscale fibers form the extra-cellular matrices or the multifunctional structural backbone for tissues and organs.
Specific junctions between these cells conduct electrical and chemical signals that result from various kinds of stimulation. The signals direct normal functions of the cells such as energy storage, information storage and retrieval, tissue regeneration, and sensing.
Analogous to nature’s design, nanofibers of electronic polymers and their composites can provide fundamental building blocks for the construction of devices and structures that perform unique new functions that serve the needs of many applications.
Nanofibers have been used in industrial, consumer and defense filtration applications for more than twenty years. Nanofibers have fiber diameters that are 100 times smaller than a human hair.
In the life sciences, nanofibers are used for a variety of applications, including biodegradable sutures, blood filtration in open heart surgery, wound dressings, drug delivery and tissue engineering.