Laser-powered spheres can haul or push 150X their weight
They don’t look like much, but these little black spheres harness the power of bright light to zip across the surface of water--pulling up to 150 times their own weight in the process. New Scientist reports that these little spheres have been developed by researchers from the Osaka Institute of Technology in Japan.
These spheres move based on an entirely different principle than, say, optical tweezers. Namely, the article describes how "the laser light causes the spheres to shed a small amount of a substance called polypyrrole that coats their surface. When released, the chemical decreases the surface tension of the water on one side of the sphere, creating a force imbalance that causes the blob to move. The results are published in Advanced Functional Materials. When used to propel a rudimentary boat, the balls were able to push along 0.05 ounces--despite weighing just 0.0003 ounces themselves. That means they can haul over 150 times their own weight."
The spheres could be instrumental in a variety of micromachine and nanotechnology applications, as well as biophotonic and microfluidic applications.