An ultrahighly sensitive and repeatable flexible pressure sensor based on PVDF/PU/MWCNT hierarchical framework-structured aerogels for monitoring human activities

Flexible piezoresistive sensors with high sensitivity and repeatability are highly desirable for monitoring human activity and human-machine interactions. However, it is still a great challenge to fabricate high-performance sensors due to the limits of multifunctional sensing platforms. In this work, hierarchical framework-structured PVDF/PU/MWCNT (PPM) aerogels fabricated by a facile thermo-assembly method were suggested as sensitive sensing platform to detect pressure and strain. The pressure-sensing platform based on optimized PPM aerogels exhibited high sensitivity of 62.4 kPa^-1 and fast response of 35 ms, which enabled the detection of minute static pressure of 3 Pa. The sensing platform was also able to detect wide-range compression from 0.5% to 90% and dynamic piezoresistive response behaviour from 1 Hz to 3 kHz, showing excellent repeatability over 50000 compression cycles and ultrahigh strain sensitivity of 156.4, which was the highest reported gauge factor. Moreover, the sensing platform with ultrahigh sensitivity and excellent repeatability enabled the monitoring of human activities, human health, human-machine interactions and non-contact actions such as music intensity. The facile fabrication and versatile capabilities of the sensing platform make it a promising candidate for wearable sensors.