Mechanical Engineering magazine has an interesting survey of a large variety of smart materials. The article covers such diverse materials as magneto-rheological fluids which become more viscous when a magnetic field is applied and piezoelectric materials that will be able to generate electricity from normal equipment vibrations. The article describes an electroactive flexible polymer one of whose neater applications is to translate the mechanical energy of a shoe hitting the ground into enough electrical energy to power a cell phone.

The system also can be used to generate electricity, by applying mechanical energy to the polymer. The film can be made to push the positive charge away from the negative, raising the voltage between the two electrodes, Pelrine said. SRI had one project to put such a device in the heel of a shoe, to generate power when a person is walking. Von Guggenberg estimated that enough electricity could be generated to power a cell phone—about one to two watts of power per step.

Another cool application under development is a biodegradable shape memory polymer that could be used to form a suture when doing endoscopic surgery.