Producing amorphous nanofibers with new techniques

Materials researchers in the US and Spain have successfully built a new technique called "laser spinning" that enables the production of amorphous nanofibers of several centimeters in length and sugars. glass is only about 35 nm. The advance of this technology is to enable the production of continuous fibers with many different and large-scale components (The results have just been published in Applied Physics Letters ).

One-dimensional pseudo-structures such as nanowires, nanotubes, nanorods . have many interesting electrical, magnetic, mechanical and optical properties. They can create many revolutions in areas such as electronics, catalysis, exploration, in composite materials, or in medicine - biology . At the present time, common fabrication methods especially developed from vapor phase or solution . and scientists are improving the technology to be able to produce continuous-length fibers with nanoscale, and at the same time have production costs low. However, such technologies only allow the production of micron-based fibers based on the extension of molten materials .

Juan Pou and colleagues at the University of Vigo and Adrian Mann and colleagues at Rutgers University have found a way to solve this problem. Researchers have developed a simple physical method that can produce very long amorphous nanofibers without requiring catalysts, samples or complex requirements. Not only can the nanofiber be created, this method also allows the fabrication of nanofibers directly from highly molten materials - which cannot be fabricated with similar methods (eg electrospinning).

Figure 1. Laboratory photo with new production equipment.

Laser spinning is a method of using a high-power laser source to produce a slice on a ceramic plate (eg silica or alumina). The new approach ensures that only a small volume of ceramic beer is transformed into a liquid state at the edge of the slice at each time. During the cutting process, an ultrasonic nozzle will spray an air stream with tremendous velocity into the cutting zone. And the viscous molten material produced will be quickly stretched and cooled very quickly by the flow of air blowing during the stretching process, leading to the creation of an disorderly structure of the nanowires (forming amorphous structure - see drawing).

"This is a very significant step forward because the physical nature (not just the chemical nature) of this technology allows the production of very long amorphous nanofibers with many different components" - Félix Quintero, the lead author of the paper , told Nanotechweb - "And the applications of this nanofiber could be nanocomposite materials, nanoparticles, sensors or new structures .". More importantly, this is a method that can be produced on a large scale with low cost and simplicity.

Figure 2. Screenshot of nanofibers with a scanning electron microscope.Angular scintigraphy is an electron diffraction spectrum that indicates the wires in an amorphous state (APL 90 (2007) 153109).

The team is working to improve this technology to better control the production process and to allow for more components. The main results of the group have just been published in Applied Physics Letters Vol. 90, pp. 153109, 2007 .

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