Flexible, self-powered, magnetism/pressure dual-mode sensor based on magnetorheological plastomer

A flexible self-powered magnetism/pressure dual-mode sensor, which consists of magnetorheological plastomer (MRP), was developed in this work. The working mechanism of the self-powered sensor was based on the displacement reaction of Fe and CuSO4. Different from traditional flexible pressure sensors, it was not only sensitive to a slight pressure (1.3 kPa), but also responsive to a small magnetic field (12 mT). Under an external magnetic field, the micro-scale carbonyl iron (CI) particles in the MRP electrode aggregated into the chain-like and the cluster-like structures, which enhanced the electrochemical activity of ions in the electrolyte of the electrode materials and formed the conductive network. The voltage increased with the magnetic field strength and the sensitivity was 4.2% at a 252 mT magnetic field. To further explore the mechanism of sensor, the microstructure evolution of CI particles inside the electrode materials under different magnetic fields was simulated by particle-level dynamics method. Finally, a smart writing board based on a self-powered magnetism/pressure dual-mode sensor array was developed and it was sensitive to different magnetic fields without an external power supply, which demonstrated a broad potential for mobile electronic device in the non-contact state.