Nano-scale coating by “NanoMATRIX” (nano-scale coating processing)

(a) SEM photograph of functional material coating on polyester fiber surface
(Coating is left on the surface by dissolving polyester fiber in alkali)

“Nanomatrix” focused its attention on the concept of “self-organization (Note 1)” with the aim of providing functionality to the fabric. By controlling the conditions (temperature, pressure, magnetic field, electrical field, humidity, additives etc) associated with the interaction and responses between the functional material and the fiber materials (polymer,) Toray succeeded in forming coatings in the order of 10 to 30nm on the surface as it became possible to control the state of molecular arrangement and/or assembly of functional materials on each of the monofilament in nano-scale sizes. Such uniform coating was not possible with the existing technology where there were non-uniform coating of the functional material in the gaps between the monofilaments and the intersections of the fabric.
By forming an even coating of the functional material on the monofilament, this technology succeeded in providing stable high functionality without losing the fabric’s texture as it solved the numerous problems such as, for example, the peeling and shedding of unevenly coated functional materials caused by stretching and contraction of the clothes in wearing them, or the problem of changes occurring in fabric texture due to binding of weave by functional agents. Also, since a continuous coating is formed due to a marked increase in the surface area that is coated, it became possible to improve the functionality and durability to much higher level than was possible before. Furthermore, combining functions with conflicting properties, such as antistatic function that requires a certain amount of water absorption and water-repellant function that keeps off water, can be achieved by controlling the state of molecular arrangement and assembly of functional materials on each of the monofilament in nano-scale sizes.

Nano-technology has been receiving even wider attention in recent years. Nano-technology can be widely classified into the “top-down approach” (lithography, microscopic processing technology etc) that processes macro-scale structures into much smaller structures and the “bottom-up approach” (nano-manipulation, which builds structures atom-by-atom or molecule-by-molecule) that builds up nano-scale or smaller size structures. It plays a major role in various areas led by the IT and medical fields.
In the textile field, even though a series of nano-tech textile products that claim nano-technology have been introduced into the market, these in fact don’t employ the latest technologies and it is clear that there exists a gap between the textile processing technology.

Under such circumstances, Toray has embarked on the development of various nano-scale technologies that exploit these latest techniques with the development concept of “seeing and understanding” and “wearing and understanding” that allows users to comprehend the difference with existing products. Among those efforts, Toray focused its attention especially on the “self-organization” concept and proceeded with research and development aimed at the mass production of textiles using “nano-scale processing technology.” As a result, Toray was able to build the technology that not only controls the voluntarily forming self-organization of nano-scale structures under certain circumstances on an industrial scale but also allows for commercialization. Though this is a complex phenomenon with many details yet to be understood, Toray has taken the first step in the technological revolution that will allow the formation of the desired nano-scale structure through self-organization as long as the controlling factors of the structure necessary for bringing out the targeted functions are known. This breakthrough facilitated the creation of production technologies that are efficient from the perspective of both resources and energy and Toray believes that this technology will change the production system of textile function processing in the future.

Toray is determined to continue with the development of new technologies that are even more technically challenging and with higher functionalities by taking advantage of nano-technology, one of the technologies in which Toray has expertise and one that plays a core role in the “Expansion of Advanced Materials Businesses” sited in the mid-term management issues “Project NT-II.”

Note 1: The concept of “self-organization” itself has not earned a scientific consensus among researchers and no clear definition exists. We consider it as a phenomenon where a molecule, due to its structure, forms a specific molecular arrangement and molecular assembly due to interaction with fiber materials (polymers) that are subjected to processing and based on the conditions of reaction (temperature, pressure, magnetic field, electric field, humidity, additives, etc.) It is considered to be a voluntary reaction that occurs under controlled conditions where it transforms from a disorganized (chaotic) state to an organized (systematic) one.
For example, though it is not nano order, a scientific experiment to grow a single crystal of sodium chloride from a water solution of salt or the formation of various types of hexagonal crystals of snow depending on weather conditions are also generally considered to be “self-organization, ” which transforms to an organized state from a disorganized one.