Researchers at MIT just developed a new bio-polymer film that is able to generate electricity from a readily available source: water vapor. The material changes its shape as it absorbs evaporated water. As the bio-polymer film repeatedly curls and unfurls it drives robotic limbs, which in turn generate enough electricity to power micro- and nanoelectronic devices.
The research team was headed by Mingming Ma, a postdoc at MIT’s David H. Koch Institute for Integrative Cancer Research. Speaking about the new material in Science magazine, Ma said: “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.”
“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,” added Robert Langer, the David H. Koch Institute Professor at MIT and senior author of the paper. The team hopes that the new bio-film will be put to use in large-scale, water-vapor-powered generators, or smaller generators for wearable electronics.
The bio-film is made of an interlocking network of two different separate polymers: polypyrrole, which forms a hard but flexible matrix that provides structural support, and polyol-borate - a soft gel which swells when it absorbs water. “By incorporating the two different kinds of polymers, you can generate a much bigger displacement, as well as a stronger force,” Guo noted.
The polymer film doesn’t require the manipulation of environmental conditions like other similar technologies. The mechanical energy generated by the material can also be converted into electricity by coupling the polymer film with a piezoelectric material (which converts mechanical stress into an electric charge), generating an average power of 5.6 nanowatts which can also be stored. In theory, the material could also be attached to clothing, where the mere evaporation of sweat could fuel devices such as physiological monitoring sensors – so you could power devices simply by sweating!
Via Science Mag