Contactless Strain Sensor Using Electret Technology for Highly Sensitive Stretch-Based Applications

The detection of mechanical stretching is usually based on piezoresistive effect made up of piezoelectric material. Here, we report a novel approach of autonomous contactless stretch sensor for detection of varying electric field based on electret technology. The present work proposes a novel approach that detects low-noise with high sensitivity for various stretch-based applications. Nanoparticle filled thin-film polymeric membrane are activated by corona injection to trap the charges and form a permanently charged electret and the contactless fixed electrode pair continuously monitors the change in electric field exerted by the tensile strain/deformation on the polymeric membrane. The sensor detects a peak output response of 4.7 V under 20% cyclic tensile strain with a sensitivity of 56 mV/%strain. By considering these merits of simple and scalable fabrication, outstanding performance and robust characteristic, we believe the autonomous contactless stretch sensor can open great opportunities not only for low-noise sensing/detection applications but can contribute to multitude large-scale applications such as intrusion detectors, microphones, pressure monitoring, sensing for security and safety applications.