Flexible and Highly Sensitive Pressure Sensors Based on Bionic Hierarchical Structures

TLDR

High-performance flexible pressure sensors are sought for wearable electronics and human–machine interfaces. The study aims to develop pressure sensors with high sensitivity and a low detection limit for practical use. Sensors are fabricated by aligning carbon‑nanotube/graphene films on microstructured PDMS molded from natural leaves, then assembling two films face‑to‑face with perpendicular CNT orientations. The resulting devices show 19.8 kPa⁻¹ sensitivity, <0.3 kPa detection limit, <16.7 ms response, 0.03 V operating voltage, and >35 000 stable cycles, indicating suitability for wearables.

Abstract

The rational design of high‐performance flexible pressure sensors attracts attention because of the potential applications in wearable electronics and human–machine interfacing. For practical applications, pressure sensors with high sensitivity and low detection limit are desired. Here, ta simple process to fabricate high‐performance pressure sensors based on biomimetic hierarchical structures and highly conductive active membranes is presented. Aligned carbon nanotubes/graphene (ACNT/G) is used as the active material and microstructured polydimethylsiloxane (m‐PDMS) molded from natural leaves is used as the flexible matrix. The highly conductive ACNT/G films with unique coalescent structures, which are directly grown using chemical vapor deposition, can be conformably coated on the m‐PDMS films with hierarchical protuberances. Flexible ACNT/G pressure sensors are then constructed by putting two ACNT/G/PDMS films face to face with the orientation of the ACNTs in the two films perpendicular to each other. Due to the unique hierarchical structures of both the ACNT/G and m‐PDMS films, the obtained pressure sensors demonstrate high sensitivity (19.8 kPa −1 , &lt;0.3 kPa), low detection limit (0.6 Pa), fast response time (&lt;16.7 ms), low operating voltage (0.03 V), and excellent stability for more than 35 000 loading–unloading cycles, thus promising potential applications in wearable electronics.