Highly sensitive flexible pressure sensor based on ionic dielectric layer with hierarchical ridge microstructure

[Display omitted] •The ionic pressure sensor based on ionic dielectric layer with hierarchical ridge microstructure shows high sensitivity.•The novel microstructure of hierarchical ridge was fabricated by a simple and low-cost way.•The novel microstructure of hierarchical ridge opens a new way of increasing the areas of the EDL.•The ionic pressure sensor shows high potential in healthcare monitoring and human-machine interaction. Although the flexible pressure sensors have been widely applied in many applications, such as human-machine interaction and electronic skins owing to their excellent mechanical robustness and fast response time, the fabrication is still not highly scalable and low-cost. Also, the sensitivity in low pressure range is not satisfactory. This paper presents a flexible pressure sensor based on the ion gel film with hierarchical ridge microstructure fabricated by a simple, scalable and low-cost way. The ionic sensor has a high sensitivity of 145.45 kPa−1 in the low-pressure range (