The material is composed of two different polymers -- one forms a hard but flexible matrix to provide structural support for the other, a soft gel. As the gel absorbs and releases water vapour it swells and shrinks, forcing the film to curl and uncurl repeatedly.
Being able to harness this motion would allow the water vapour to be used to generate electrical power.
"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," said lead author Mingming Ma, a postdoc at MIT's David H Koch Institute for Integrative Cancer Research.
The 20-micrometre-thick polymer film is able to take advantage of very small amounts of moisture. In the video above you can see pieces of the film absorbing evaporated water from a damp surface and beginning to curl up. Once the bottom layer is exposed to the air it releases the moisture and uncurls before beginning the process again. As a result the chemical energy of the water gradient can be transformed into mechanical energy.
"We are very excited about this new material," said senior author Robert Langer, the David H Koch Institute professor at MIT. "We expect as we achieve higher efficiency in converting mechanical energy into electricity, this material will find even broader applications."
wired
------------------------- *Leave a comments, questions or even a suggestions below this post. Your expressions are always welcomed.
0 comments:
Post a Comment