New material, created by MIT engineers, absorbs tiny amounts of water vapor. This process changes the shape of the material and initiates a continuous motion, harvesting enough energy to power nanoelectronic devices.
According to says Mingming Ma, a postdoc at MIT’s David H. Koch Institute for Integrative Cancer Research, and lead author of the publication released in the latest issue of Science, such material can minimize the need of changing batteries often.
The material is made of two different polymers– polypyrrole and polyol-borate. Both are included in an interlocking network to provide structural support and absorb water. Incorporating both polymers, allowed the researchers to generate large displacement and strong force.
The film is only 20-micrometers thick. When placed on a moist surface, the film curls exposing the bottom of the film to air. This makes the water evaporate and the film starts curling again. The continuous motion converts the chemical energy of the water gradient into mechanical energy.
As Ma states, the material needs very small amount of moisture, and if coupled with piezoelectric material, the mechanical energy can be converted into an electric charge.
The team is proud to present their material and everyone is convinced that they can achieve even higher efficiency in converting mechanical energy into electricity. The applications of the material vary from large-scale, water- vapor-powered generators, to small generators to power wearable electronics.
The system can easily generate an average power of 5.6 nanowatts. On a larger scale, if placed above a lake or a river, it can harvest energy directly from the environment. The authors also suggest that it can be attached to clothing, making use of sweat to power small portable devices.
The researchers are currently busy with improving the efficiency of the conversion of mechanical energy to electrical energy, so that small films can be used to power large devices.