Longfei Zhang, Guowei Gao
In view of the demand for wearable physiological monitoring, porous PDMS/MWCNTs composite films were fabricated via the sacrificial template method in this work. Output performance tests were carried out on films with different sacrificial particle sizes, film thicknesses, and multi-walled carbon nanotube (MWCNT) mass fractions. Scanning electron microscopy (SEM) was employed for structural morphology characterization. The optimal particle size, thickness, and doping ratio were confirmed to be 63 μm, 3 mm, and 9 wt%, respectively, and flexible sensor arrays based on triboelectric nanogenerators were further fabricated. In this paper, a complete signal conditioning system consisting of a flexible sensor array and a signal acquisition circuit (including a power supply unit, reset circuit, signal conditioning module, and core control chip) was designed to realize data transmission and upper computer display. Pulse signals from four volunteers were collected in five groups, respectively, for comparative analysis. Experimental results reveal that multiple sets of pulse data from the same subject show high consistency. Slight deviations within 0.38 V are merely caused by breathing and other subtle interference factors. These results verify that the prepared sensor possesses favorable sensitivity and repeatability.