Flexible capacitive sensor based on Miura-ori structure

Abstract

Flexible capacitive pressure sensors have been widely used in applications ranging from healthcare monitoring to human − machine interaction. However, it remains a huge challenge to overcome the sensitivity attenuation with increasing pressure, as well as maintain sensing performance at high stretching. Herein, inspired by the Miura-ori structure, a Symmetrical Miura-ori Capacitive sensor (SMC sensor) is proposed to realize a positive correlation between sensitivity and pressure within a tunable pressure range, which can be adjusted by modifying the SMC sensor structures. The capacitance is determined through the synergistic effect of distance and opposite area between electrodes conformal to the Miura-ori structure. The SMC sensor exhibits a maximum sensitivity of 0.648 kPa−1 and high stability over 1000 cycles of compression and stretching. Furthermore, the special folding model of the Miura-ori structure avoids shape attenuation in sensitivity during stretching and detects both contractive and stretched strains. These unique characteristics make the proposed sensor promising for general physiological signal monitoring, even with high stretching and environmental adaptability.