Lithography-Free Formation of Controllable Microdomes via Droplet Templates for Robust, Ultrasensitive, and Flexible Pressure Sensors

Wearable pressure sensors with excellent flexibility and sensitivity have emerged as a promising field for electronic skin, healthcare monitoring, and so forth. Herein, we report a flexible, tunable resistive pressure sensor based on the carbon powder/polydimethylsiloxane (CPDMS) conductive layer and the microdome-structured PDMS membrane through a simple, lithography-free, and low-cost replication method. The wearable pressure sensor was produced by replicating the dome-shaped structure from water droplets on glass substrate and spray-coating the conductive layer (CPDMS) on the dome-structured membrane afterward. The domes with different heights and bottom diameters for sensor optimization can be simply obtained by regulating the sizes of water droplets sprayed on the glass substrate. The optimized sensor exhibits the high sensitivity of 124 kPa–1 (0–200 Pa), 0.39 kPa–1 (0.2–12 kPa), and 0.02 kPa–1 (12–50 kPa) as well as the detection limit of 2 Pa. Furthermore, the flexible pressure sensor based on the interlocked domed structure was presented as a multifaceted tool to precisely monitor various physical signals or pressure sources, e.g., finger bending/touching, gas flowing, voice vibration, tiny pressure, and so on. We believe that the demonstrated economical methodology can be of profound significance for applications including artificial skins, interactive robotics, flexible electronic devices, and other related fields in the future.