The miniaturized, lightweight electronics of the near future may be powered by origami. You know, folded paper. This bit of sci-fi is already quite real: A method of power generation developed by physicists at the Georgia Institute of Technology, which is described in this month's edition of ACS Nano, may someday soon power the internet of things using just old-school arts and crafts.
There's really nothing all that exotic about the idea. It's just static electricity of the sort one might experience dragging their feet along some carpet. When the right materials come into contact and separate again repeatedly, the effect is of one surface effectively stealing electrons from the other and, thus, garnering some extra electric charge. That charge might be released painfully from finger to brass doorknob, or it might be used to power some biological nanosensor.
The method of building up a charge described above is more technically known as triboelectricity or the triboelectric effect. When the two surfaces come into contact, a brief chemical bond occurs, which is called adhesion. The electrons on either side of the bond scoot around such that the electrochemical potentials of the two materials is in equilibrium, and when the materials separate again, some electrons stay behind. And so a charge builds up.
The Georgia Institute researchers started with plain old printer paper, onto which they glued sheets of aluminum foil and Teflon. Then it was just a matter of folding the stuff into different shapes and seeing what might happen. Of particular interest was the Slinky-shaped configuration, which you can see above. As the different rings come into contact and separate again, charge is accumulated.
The design was able to generate about 0.14 watts per square meter—via 2 microAmperes of current—enough to power four commercial LEDs at once. This electricity was harvested simply enough via copper wires running along the aluminum foil. As an IEEE summary notes, the same configuration could be used alternatively as a pressure sensor, e.g. mechanical force revealed through charge.
It's not free electricity, of course. It is still necessary to apply a mechanical force to get power from one of these triboelectric nanogenerators, but at these scales it's a lot easier to find untapped sources of mechanical energy, particularly when it comes to the human body.
"The as-fabricated TENGs are capable of harvesting ambient mechanical energy from various kinds of human motions, such as stretching, lifting, and twisting," the current paper explains. You could be powering the internet of things right now.