Self-powered low hysteresis piezo-ionogel sensor for measuring static pressure

초록

In this study, a self-powered piezo-ionic pressure sensor with high linearity and excellent static response was developed. The proposed sensor can output an electric signal in response to mechanical stress without an external power source due to the piezoelectric effect and maintains a stable output under static pressure by inducing an ion migration phenomenon. Poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), polyvinyl chloride (PVC), and ionic liquids (ILs) were used as ionogel materials. In particular, the hysteresis of the piezoionogel was reduced by blending PVDF-TrFE and PVC, which demonstrates the potential of this new sensing material in future piezoelectric-ionic applications. We optimized the mixing ratio by considering the mechanical, chemical, and electrical properties of the blended ionogel, and successfully fabricated a pressure sensor that can measure static pressure over a wide range of pressure stimuli from 10 kPa to 800 kPa. The sensor showed high linearity (R2: 0.982) and long-term stability (less than 1 % signal change after 1000 cycles). To implement a smart glove inspired by human mechanoreceptors, 16 sensors were integrated into a glove to measure pressure distribution when grabbing an object. Based on the data, we were able to successfully distinguish the stiffness of each material based on the grip force of the object detected in the glove, and this can be expanded into technology for the recognition function of each object. This PVDF-TrFE/PVC ionogel and sensor can be used in smart sensors, wearable devices, and wearable robots in the future.

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