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Categories: smart-materials-smt nanofibers
Cotton continues to be the most commonly used and popular clothing material. It is not only renewable but also biodegradable and readily available. Since cotton is composed mainly of cellulose molecules, adding functionality to cotton fibers is a challenging endeavor as physical and chemical heterogeneities need to be overcome. For example, the cross section of a cotton fiber is nonplanar and has convex and concave surfaces with high curvature that prevent the use of traditional surface chemistry techniques. Furthermore, cotton fibers are twisted along their axes, which adds complexity to existing surface treatments. Cotton fibers are also chemically heterogeneous since different crops exhibit different properties depending on the conditions of the soil, weather, and processing. Therefore, wet chemistry methods rather than physical ones appear to be more robust and able to modify the surface of natural fibers.
In the current issue of Materials Today, Juan P. Hinestroza looks at how materials scientists are using nanotechnology to enhance the properties and performance of cotton. Nanoparticles can impart antibacterial properties on cotton, decompose harmful gases or toxic chemicals, and affect the color, texture, and comfort of cotton fabrics. The ability to control color in fabrics in a tunable fashion, without the use of dyes, while adding functionality is a makeover for the old faithful, cotton; it is a match between fiber science and apparel design made possible by nanotechnology.
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Posted by: The Editors
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Categories: molecular-manufacturing molecular-machines--devices
In his 1986 book, Engines of Creation, K. Eric Drexler set down the long-term aim of nanotechnology – to create an assembler, a microscopic robot that could construct products from a stock of atoms and molecules. For the last two decades, researchers who recognized the benefits of achieving molecular manufacturing have used top-down and bottom-up methods to develop molecular machines. The top-down approach is seen in the manipulative power of the atomic force microscope (AFM), a machine that can observe and handle single atoms, and the bottom-up approach uses chemistry to build molecular machinery. However, neither the top-down nor the bottom-up approach is yet to fulfill Drexler’s prophecy of functional nanobots that can construct other machines and useful products.
The first real steps towards building a microscopic device that can construct nanomachines have recently been taken by researchers at the National Institute of Standards and Technology (NIST) in the US. Soon to be published in the peer-reviewed publication International Journal of Nanomanufacturing, researchers from the NIST’s Intelligent Systems Division have described an early, proto-prototype for a nanoscale assembler.
Jason Gorman, of the Intelligent Systems Division, concedes that, “Nanoassembly is extremely challenging.” Yet the rewards could be enormous with the ultimate potential of creating a technology that can construct almost any material from atoms and molecules from super-strong but incredibly lightweight construction materials to a molecular computer or even nanobots that can make other nanobots to solve global problems, such as food, water, and energy shortages. “Our demonstration is still a work in progress,” says Gorman, “you might describe it as a ‘proto-prototype’ for a nanoassembler.”
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Posted by: The Editors
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