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

•The artificial electronic skin was developed by constructing high-aspect-ratio interlocked ZnO nanorods, which can induce a change in the contact area to improve the sensor sensitivity under static and dynamic pressure.•The e-skin with interlocked ZnO nanorods could monitor personal artery pulse pressure and artery stiffness in real time by using a noninvasive method.•The proposed ZnO nanorod e-skin can differentiate multiple mechanical stimuli, normal force, bending, and torsion through different waveforms because of its unique interlocked geometry.•For different types of repeated mechanical stimuli applied to the e-skin through finger touching, the corresponding signal intensity changes relative to the electrical resistance.•ZnO nanorods are n-type semiconductors with a negative temperature coefficient, which provides high-temperature sensitivity to fabricate the sensor due to the lower thermal activation energy.•This paper proposed 3 × 3 pixel sensor array on the flexible substrate for multitouch applications, which enabled to represent the corresponding location and magnitudes of the applied pressures in the graphic interface. 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.