(Invited) Biomimetic Electronic Skins for Wearable Sensors

Abstract

Flexible physical sensors with high sensitivities have gained great attentions in the fields of wearable sensors, robotic skins, and biomedical diagnostics. Here, we introduce several biomimetic approaches to develop high-performance flexible electronic skins and their applications in wearable sensors. First, by mimicking the structures and functions of fingertip skin, we introduce highly-sensitive, multifunctional, and stretchable electronic skins. Inspired by the interlocked microstructures found in epidermal-dermal ridges in human skin, piezoresistive interlocked microdomes are employed for the demonstration of stress-direction-sensitive, stretchable electronic skins. We show that interlocked microdome arrays possess highly direction-sensitive detection capability of various mechanical stimuli including normal, shear, stretching, bending, and twisting forces. We also demonstrate that ferroelectric skins with fingerprint-like patterns and interlocked microstructures can detect and discriminate multiple spatio-temporal tactile stimuli including static and dynamic pressure, vibration, and temperature with high sensitivities. For wearable device applications, we show that stretchable electronic skins attached on the human skin can be used as wearable healthcare monitoring devices, which are able to distinguish various mechanical stimuli applied in different directions, selectively monitor different intensities and directions of air flows and vibrations, and sensitively monitor human breathing flows and voice vibrations. In addition, dynamic touch sensing ability is employed for precise detection of acoustic sounds, and discrimination of various surface textures. For skin attachable devices, we also introduce smart adhesive pads based on octopus-inspired theremoresponsive adhesive pads. Finally, we demonstrate conductive and ultrathin nanomembranes for skin-attachable microphones and speakers.