Silver nanowire-embedded PDMS with a multiscale structure for a highly sensitive and robust flexible pressure sensor

TLDR

Highly sensitive, low‑cost pressure sensors are needed for electronic skins and wearable devices. The study presents a low‑cost, facile fabrication strategy for multiscale‑structured elastomeric electrodes and a highly sensitive, robust flexible pressure sensor. The sensor is fabricated by inducing spontaneous buckling of PDMS and embedding silver nanowires to form a multiscale electrode, which is then laminated onto a dielectric/bottom electrode template. The resulting capacitive sensor achieves >3.8 kPa⁻¹ sensitivity, <150 ms response/relaxation, excellent bending and cycle stability, and can be scaled into arrays that map spatial pressure, enabling fingertip devices to detect pressure distribution across each finger.

Abstract

The development of highly sensitive pressure sensors with a low-cost and facile fabrication technique is desirable for electronic skins and wearable sensing devices. Here a low-cost and facile fabrication strategy to obtain multiscale-structured elastomeric electrodes and a highly sensitive and robust flexible pressure sensor is presented. The principles of spontaneous buckle formation of the PDMS surface and the embedding of silver nanowires are used to fabricate the multiscale-structured elastomeric electrode. By laminating the multiscale-structured elastomeric electrode onto the dielectric layer/bottom electrode template, the pressure sensor can be obtained. The pressure sensor is based on the capacitive sensing mechanism and shows high sensitivity (>3.8 kPa(-1)), fast response and relaxation time (<150 ms), high bending stability and high cycle stability. The fabrication process can be easily scaled up to produce pressure sensor arrays and they can detect the spatial distribution of the applied pressure. It is also demonstrated that the fingertip pressure sensing device can sense the pressure distribution of each finger, when grabbing an object.