A soft dielectric material that creates a relatively high voltage when bent has been created by physicists in China. Qian Deng and colleagues at Xi’an Jiaotong University describe their material as the first-ever “flexoelectret”. It was made by embedding a charged polymer layer in the middle of a dielectric silicone rubber material. With some improvements, the new material could find a wide range of applications including wearable electronics.
When some materials are deformed non-uniformly, a strain gradient drives positive and negative ions apart to create a voltage across the material. Known as flexoelectricity, this effect is observed in many dielectric materials, including crystals, polymers, and semiconductors.
The effect is usually strongest in brittle ceramic materials, which are unsuitable for practical applications such as stretchable electronics. While far higher strain gradients can be achieved in softer dielectric materials, flexoelectric voltages generated in these materials are typically several orders of magnitude smaller than in ceramics.
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