Contactless strain sensor using electret technology for hig hly 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.