Cover Image, Volume 134, Issue 10

Cellular nonpolar polymer films having eye‐like cell shape structure can present piezoelectric‐like behavior by submitting the materials to a high electric field. These materials are named ferroelectrets. Piezoelectricity in ferroelectrets results from positive and negative electrical charges created on the opposite faces of each cell surface during a charging process. A more elongated eye‐like cell shape structure can be obtained using a post‐processing thermal‐pressure treatment, resulting in a higher piezoelectric property. Denis Rodrigue and colleagues explain how these new materials, as a result of their low material and processing costs, are currently under study for several applications, such as actuators, vibration control, energy conversions, speakers, microphones, sensors. (DOI: 10.1002/app.44577 )