Dual-porous structured dielectric layer for soft capacitive pressure sensor with high sensitivity

Highly sensitive, soft pressure sensors are urgently required in wearable electronics and robotics applications. In this study, we fabricated a dual-porous structured elastomer using a simple and cost-effective method, in which yeast and sugar particles were introduced into Ecoflex solution. The combination of yeast fermentation and sugar particle dissolution resulted in a dual-porous elastomer consisting of both large closed pores and small open pores. The dual-porous elastomer was employed as the dielectric layer in a soft capacitive pressure sensor. The pressure sensor exhibited a sensitivity over six times higher than that of the sensor with a mono-porous elastomer-based dielectric layer in the pressure range of 1–10 kPa. The finite element simulation demonstrated that the sensitivity enhancement can be attributed to the significantly low stiffness and buckling load resulting from the presence of large closed pores. Finger-attached sensors and motion-monitoring systems demonstrated a wide range of potential applications in wearable electronics.