Plant‐Based Biodegradable Capacitive Tactile Pressure Sensor Using Flexible and Transparent Leaf Skeletons as Electrodes and Flower Petal as Dielectric Layer

Abstract In biomedical sciences, there is demand for electronic skins with highly sensitive tactile sensors, having applications in patient monitoring, human–machine interfaces, and on‐body sensors. In clinical applications, it would be especially beneficial if the sensors would be disposable. Here, an all plant‐material‐based biodegradable capacitive tactile pressure sensor for disposable electronic skins is reported. Silver‐nanowire‐coated leaf skeletons are used as breathable and flexible electrodes while freeze‐dried rose petals are used as the dielectric layer. The leaf skeleton electrodes have a rough fractal‐like architecture, which provides good adhesion to the silver nanowires and maintains interconnections between the silver nanowires when the electrodes are bent. The electrodes display low constant resistance up to curvature of 800 m⁻¹. The rose petal dielectric layer has a multiscale 3D cell wall microstructure, which compresses elastically when subjected to pressure. The fabricated sensor can respond to pressures ranging from 0.007 to at least 60 kPa, with a maximum sensitivity of ≈0.08 kPa⁻¹. The signal is stable for at least 5000 pressure cycles, after an initial break‐in period. Owing to the all biomaterial constituents, the sensor is biodegradable under aqueous conditions. The sensor is successfully applied as an e‐skin in touch sensing and gesture monitoring.