High sensitivity capacitive flexible pressure sensor based on PDMS double wrinkled microstructure

Capacitive pressure sensors are an important part of wearable human health applications. The fabrication of highly sensitive flexible pressure sensors in a low cost and efficient way remains a tough issue. Herein, a rapid-response and highly sensitive capacitive pressure sensor is developed based on compressible wrinkled microstructures through a low-cost and scalable solution approach. The sensor is constructed of double layers of well-defined polydimethylsiloxane (PDMS) structures with silver-nanowires (Ag NWs) electrodes. This capacitive pressure sensor allows the sensitive detection of both static and dynamic external stimuli. When the double layer PDMS wrinkled direction is perpendicular to each other, the prepared sensor possesses a high sensitivity of 3.19 kpa⁻¹, a low detectable pressure limit (1.0 Pa), a fast response time (< 100 ms), and a wide pressure range. The sensor also possesses high robustness: it can be tested for at least 1800 cycles without performance deterioration. We further demonstrate this highly sensitive pressure sensor in a wearable application.