A soft tactile sensing array with high sensitivity based on MWCNTs-PDMS composite of hierarchically porous structure

Abstract

The advancement of wearable tactile sensors that involves with high sensitivity under ultra-low pressures is crucial for varieties of human-machine interactive applications, like smart phones, healthcare monitoring, and electronic skins. Here in this paper, a soft capacitive tactile sensing array is introduced based on hierarchically porous multi-walled carbon nanotubes (MWCNTs)-polydimethylsiloxane composite, which leads to sensitivity improvement attributing to a synergistic effect of the hierarchically porous elastomer and conductive MWCNTs supplements. The proposed device exhibits superior pressure-sensing performances, with high sensitivity (3.58 kPa−1) under small mechanical stimuli (<80 Pa), broad measuring range (0–265 kPa), fast response time (<45 ms), good repeatability, minimum limit of detection (<10 Pa), as well as low-hysteresis, allowing efficient sensing of pressure from all types of sources, from vulnerable signals such as human breathing, artery and venous pulses, and soft human finger touch to possible brutal variations such as sudden change of object weight or prompt collide. Moreover, extensive body attached experiments confirm that the soft tactile sensing array is fully human compatible and capable for a variety of human-machine interfaces and health monitoring applications.