Highly Sensitive Temperature-Pressure Bimodal Aerogel with Stimulus Discriminability for Human Physiological Monitoring.

ABSTRACT

Multimodal sensor with high sensitivity, accurate sensing resolution, and stimuli discriminability is very desirable for human physiological state monitoring. A dual-sensing aerogel is fabricated with independent pyro-piezoresistive behavior by leveraging MXene and semicrystalline polymer to assemble shrinkable nanochannel structures inside multilevel cellular walls of aerogel for discriminable temperature and pressure sensing. The shrinkable nanochannels, controlled by the melt flow-triggered volume change of semicrystalline polymer, act as thermoresponsive conductive channels to endow the pyroresistive aerogel with negative temperature coefficient of resistance of -10.0% °C-1 and high accuracy within 0.2 °C in human physiological temperature range of 30-40 °C. The flexible cellular walls, working as pressure-responsive conductive channels, enable the piezoresistive aerogel to exhibit a pressure sensitivity up to 777 kPa-1 with a detectable pressure limit of 0.05 Pa. The pyro-piezoresistive aerogel can detect the temperature-dependent characteristics of pulse pressure waveforms from artery vessels under different human body temperature states.