Rose petals bioinspired microstructure for flexible tactile electronic skin

To improve the sensitivity and accuracy of the flexible electronic skin, inspired by the micro-nano hierarchical structures on the surface of rose petals, we conducted a study on the high sensitivity of the flexible tactile electronic skin using a simple, efficient and low-cost two-step sacrificial template method, and successfully prepared a flexible capacitive sensor based on AgNWs/PVDF composite dielectric layer and PDMS microstructured electrode of the bionic rose petal. The results show that the sensitivity of the sensor is maximum when the AgNWs content is 30 wt.%, and the minimum detectable stress is 0.32 kPa⁻¹, which is 1.6 times higher than that of the pure PVDF film as the dielectric layer, and the capacitance is up to 157.6 pF at this time. The capacitive flexible pressure sensor can easily load over 1000 times of stress loading/unloading (50 N), showing excellent cyclic stability. Based on the super hydrophobicity and high adhesion (Cassie impregnating state) brought by the petal effect, the PDMS microstructured flexible electrode can inhibit the growth of bacteria to a certain extent in cooperation with AgNWs/PVDF dielectric layer, while avoiding the deposition of liquid droplets in the dielectric layer, which provides a new idea to solve the problem of electronic skin failure caused by body fluid contact. It is of positive significance to achieve an efficient and simple strategy to solve the problems of low sensing sensitivity, long response time and poor stability.