MIT engineers have developed a new polymer film which can take advantage of the chemical energy in a water gradient and turn it into mechanical energy; which in turn can then be converted into electricity.
The film is made from an interlocking network of polypyrrole, which forms a hard but flexible matrix that provides structural support, and polyol-borate, which is a soft gel that swells when it absorbs water.
When the plyol-borate (which is on the bottom of the polymer film) absorbs water, even the tiniest amount, it expands, forcing the film to curl up and move away from the surface. Once exposed to the air it then dries out as the moisture evaporates, somersaults forward, and then begins the process again. By connecting the polymer to a piezoelectric material, the mechanical motion can be converted into electricity, enough to power nanoelectronic devices.
Related Article: A Look at China's Renewable Energy Progress
Mingming Ma, a postdoc at MIT’s David H. Koch Institute for Integrative Cancer Research and one of the lead authors of the paper, explained that “with a sensor powered by a battery, you have to replace it periodically. If you have this device, you can harvest energy from the environment so you don't have to replace it very often.”
Robert Langer, another lead author and Professor at the David H. Koch Institute, said that, “we are very excited about this new material, and we expect as we achieve higher efficiency in converting mechanical energy into electricity, this material will find even broader applications.”
By. James Burgess of Oilprice.com