Plastic Film Mimics Muscle Movement

Artificial muscles, skin, and organs that move like the real thing. That's just one set of possibilities for a polymer that moves in response to an electrical voltage, says Qi-Ming Zhang, an associate professor at Pennsylvania State University, University Park. The researchers started with a material that was originally developed for clear plastic bags and enhanced its electrostrictive response by 40 times. (Electrostrictive materials are similar to piezoelectric materials, but are not polarized.) The altered material has a deformation rate under a high electric field of 4%, or a 4-in. change for every 100 in. Researchers say flexibility, pliability, and ease of manufacture make the material ideal for use in medical imaging equipment, underwater detectors, and stereo speakers. Because of its high dielectric constant, the material could be used for capacitors.