Novel flexible capacitive pressure sensor with a wide detection range enabled by carboxyl iron particle-paraffin wax/silicone composite

The emergence of flexible capacitive pressure sensors has prominently accelerated the development of flexible electronics. However, most capacitive pressure sensors reported so far have limited detection ranges, which greatly restricts their application scenarios. In this work, a novel flexible capacitive pressure sensor with a wide detection range was produced by employing the carboxyl iron particle-paraffin wax (CIP-PW)/silicone composite as the dielectric layer. Due to the introduction of phase-changing PW and magnetic CIPs, the resultant CIP-PW/silicone composite exhibits magnetism and temperature-controllable mechanical properties, which therefore provides the capacitive pressure sensor with a tunable effective detection range in the frequency range of 0.1–5 Hz. To be specific, the sensor could achieve an effective detection range of 0.2–350 kPa, much wider than other capacitive sensors reported. This merit is further demonstrated by monitoring finger and arm movements as well as walking status. In addition to the physical contact sensing, the sensor exhibits a contactless sensing capacity, and could be used to monitor finger movements without direct contact. In virtue of the wide detection range and bimodal sensing capacity, the current capacitive pressure sensor shows greatly promising in the fields of wearable devices, e-skin, robotics and so on.