A flexible multifunctional tactile sensor using interlocked zinc oxide nanorod arrays for artificial electronic skin

In the development of artificial electronic skin (e-skin), a flexible tactile sensor is a critical component that imitates human skin response to dynamic and static stimuli. In this study, we developed a novel multifunctional tactile sensor to mimic human skin with high force sensitivity, high flexibility, and temperature measurable performance. The unique geometry of the interlocked structures enabled differentiation between different mechanical stimuli, including pressure, bending and torsion forces. The substrate was flexible because of the material properties of the polydimethylsiloxane (PDMS) layer. The top electrode and bottom electrode layers were interlocked by high-aspect-ratio zinc oxide nanorods (NRs), which were grown vertically on the PDMS surface, providing high sensitivity for the measurement of contact force and environmental temperature. Moreover, the sensor was applied for measuring and monitoring arterial pulse pressure. Thus, we successfully fabricated a 3 × 3 sensor array with multiple functions, which were verified through experiments. In the future, the proposed tactile sensor can be used in wearable health care devices, flexible interfaces, and bionic robotic skins in the industry.