Tunable, Ultrasensitive, and Flexible Pressure Sensors Based on Wrinkled Microstructures for Electronic Skins

Flexible pressure sensors play an important role in electronic skins (E-Skins), which mimic the mechanical forces sensing properties of human skin. A rational design for a pressure sensor with adjustable characteristics is in high demand for different application scenarios. Here, we present tunable, ultrasensitive, and flexible pressure sensors based on compressible wrinkled microstructures. Modifying the morphology of polydimethylsiloxane (PDMS) microstructure enables the device to obtain different sensitivities and pressure ranges for different requirements. Furthermore, by intentionally introducing hollow structures in the PDMS wrinkles, our pressure sensor exhibits an ultrahigh sensitivity of 14.268 kPa^-1. The elastic microstructure-based capacitive sensor also possesses a very low detectable pressure limit (1.5 Pa), a fast response time (<50 ms), a wide pressure range, and excellent cycling stability. Implementing respiratory monitoring and vocalization recognition is realized by attaching the flexible pressure sensor onto the chest and throat, respectively, showing its great application potential for disease diagnosis, monitoring, and other advanced clinical/biological wearable technologies.