Compounds of polyvinylidene fluoride and carbon nanofibers have proven to be the best piezoelectric composite ever made thus far. Along with other properties, the materials produce electricity when they are stretched. The development and potential applications of this new material were presented by Dr. Walter Voit of the University of Texas at Dallas at the session of the annual meeting of the American Chemical Society.
Polyvinylidene fluoride is already used in pressure sensors in touchpads and other applications. The addition of single-walled carbon nanotubes and organic nanostructures known as “buckyballs” has been found to double the electric output of the material when stretched. Incremental adjustments of the new materials are still in progress to develop the most electric potential possible. One of the refinements is simply twisting the carbon nanotubes so that the overall composite has greater strength. The twisting also increases the electrical output.
Composites of polyvinylidene fluoride have numerous potentially “green” applications. Muscle fibers for use as replacements for human muscle are possible. The same levels of elasticity are expected to find a large number of applications in industry. Sheets of the material are being tested in aircraft seats as an energy source. Electricity is produced when people move the fabric by sitting and getting up. The electricity produced could power parts of an airplane or eliminate the need of heavier tubing or wiring.
Prototype muscle fibers that are the width of ten strands of human hair have been produced from polyvinylidene fluoride. The tiny fiber can lift 16 pounds when heated and contract by 50 percent. The developers consider the materials to be the best piezoelectric composite ever made thus far.
