Process for Collecting and Spinning Nano-Fiber Yarns

Licensing Technology Network

Research indicates that the market for textiles — alone — that make use of nanotechnologies will reach US $13.6 billion this year, growing to US $115 billion by 2012. Nano-fibers can be altered at the molecular level, creating advanced fabrics that can be 100 times lighter in weight, 100 times stronger, and up to 100 times lighter than conventional fabrics, and use one-hundredth the amount of material.

None of the existing patented methods, however, has resulted in the spinning of long enough yarns, or yarns that are commercially viable enough to be adopted by mainstream industry. This new technology overcomes the problems experienced with previously patented approaches. It results in a quality twisted yarn and produces these yarns in quantities and at speeds that would make production of these yarns commercially viable.

What has been needed by the industry is the bulk availability of commercially viable nano-fiber yarns with controlled orientation of nano-fibers. This allows processing of nano-fibers by traditional textile processing methods, such as weaving, knitting, and embroidery. The properties of nanofibers lead to the potential application of electro-spun fibers in such diverse fields as high-performance filters, absorbent textiles, fiber-reinforced composites, biomedical textiles for wound dressings, tissue scaffolding and drug-release materials, nano– and microelectronic devices, electromagnetic shielding, photovoltaic devices and high-performance electrodes, as well as a range of nano-fiber-based sensors.

Differences between traditional and nano-fibers

Traditional textile fibers have diameters in the range of microns to millimeters.

When looking at nano-fiber, definitions vary, with some people calling any fiber with a diameter below 1 micron a nano-fiber, while others insist that you can only call them nano-fiber if they have diameters below 100nm.

Regardless of which definition you use, nano-fibers have very low diameters, at least one or two orders lower than traditional textile fibers.

As fiber diameter decreases, the surface-to-volume ratio, and also the specific surface area of the material increases.

This increase in specific surface area of the material has significant influence on the chemical properties.

The high surface-to-volume ratio means that most of the material is on the outside of the fiber. So, if you have some chemical reaction that takes place on the surface of the fiber, a high specific surface area implies that there will be more surface area per gram of the fiber. If, for instance you use the fiber to catalyze a chemical reaction (or as a catalyst support) and the reaction has a rate of conversion of 2grams/hour on a 1 square meter surface, then the increased surface area of the 200nm nano-fiber can theoretically lead to a 100-fold increase in the throughput rate over a traditional 20 micrometer fiber, due to the high surface area.

This new technology is simple, can scale up, results in a high degree of fiber alignment, and works for most polymers and/or polymer blends that can be electro-statically spun into fibers. Now any textile producer will be able to place a bobbin of nano fiber yarn on his existing machine and produce products for the future.

More extensive information appears in the accompanying TechPak.

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