A high-sensitivity flexible pressure sensor based on graphite-modified magnetorheological elastomer

Abstract Flexible capacitive sensors based on magnetorheological elastomers (MREs) offer advantages such as fast response and high stability, holding promise as ‘electronic skin’ for humanoid robots. However, conventional MREs suffer from low sensitivity in capacitive sensor applications. This paper reports a graphite-modified MRE (GMRE). Isotropic and anisotropic GMRE samples with various composition ratios were fabricated, and their capacitive response behaviors under magnetic fields and pressure were systematically investigated. Experimental results indicate that the incorporation of graphite significantly enhances the sensitivity of MREs. Structural processing further improves both the magnetic field sensitivity and pressure sensitivity of GMREs. The GMRE sample with an n Fe : n gr ratio of 5:2 exhibits the best overall performance. A GMRE sensor using Sample S3( n Fe : n gr = 5:2) as the sensing element was fabricated. Test results demonstrate that this sensor possesses high sensitivity (0.634 kPa −1 ), high linearity ( R 2 ⩾ 0.9865), a wide measurement range (0–374kPa), as well as high response speed (92 ms) and cycling stability. The sensor also shows good reliability and accuracy in applications such as Morse code communication and real-time gesture recognition. This study provides a theoretical and experimental foundation for developing high-performance flexible pressure sensors.