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Posted on: 3/4/2013 12:00:00 AM... Researchers from North Carolina State University have developed a way to melt or “weld” specific portions of polymers by embedding aligned nanoparticles within the materials. Their technique, which melts fibers along a chosen direction within a material, may lead to stronger, more resilient nanofibers and materials.

The project involved placing specifically aligned gold nanorods within a solid material. Gold nanorods absorb light at different wavelengths, depending upon the size and orientation of the nanorod, and then they convert that absorbed light directly into heat. In this case, the nanorods were designed to respond to light wavelengths of 520 nanometers (nm) in a horizontal alignment and 800 nm when vertically aligned. Humans can see light at 520 nm, while 808 nm is in the invisible, near-infrared spectrum.

When the different wavelengths of light were applied to the material, they melted the fibers along the chosen directions, while leaving surrounding fibers largely intact.

The researchers have noted that being able to heat materials spatially in this way enhances the ability to manipulate very specific portions of these materials. The technique can also be used to optimize materials that have already been manufactured, since heating at the nanoscale can change the mechanical characteristics of objects, without affecting their physical properties.

For More Information:

• Access "Anisotropic Thermal Processing of Polymer Nanocomposites via the Photothermal Effect of Gold Nanorods"

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