When a liquid is falling through space, like a raindrop, it forms a spherical shape. The molecules of the liquid are all weakly attracted to each other and pull together to form the spherical drop. But let's say that the liquid is a conductor of electricity, and is near an electric field. The field will pull on the molecules more than their natural cohesive force does, and the part of the drop nearest the field will be pulled into a cone. As the force pulling on the drop gets bigger, the cone will get higher until a thin jet of liquid comes out.
This is electrospraying. When the liquid comprises molten chains of polymers, the spray will suddenly form into a long, spiraling strand. A nanofiber just assembles itself. This is electrospinning. And it looks cool.
Right now, they're working on electrospinning fibers that might help in medical dressings, or form the matrix for tissue growth. The tiny strands might be worked into a fabric on which cells can be deposited. Which would make an even cooler video, so we can live in hope that that happens soon.
[Via Cornell University]