Self‐Powered Wearable Micropyramid Piezoelectric Film Sensor for Real‐Time Monitoring of Blood Pressure

Abstract

Cardiovascular diseases can be prevented in advance by noninvasive and continuous real‐time measurement of blood pressure using a wearable sensor. Among many recent developments, piezoelectric sensors demonstrate the possibility to monitor blood pressure continuously without relying on an external energy input. However, most of the piezoelectric‐sensor research focuses on the property enhancement of piezoelectric materials without systematic investigations of how sensor performance is influenced by the microgeometry and electrode configuration of piezoelectric sensor. Herein, the micropyramid‐assisted piezoelectric film (MPF) sensors are designed and constructed and their performances are investigated both experimentally and by finite‐element modeling (FEM) simulations. The sensor signal that is strongly coupled to both stress amplification and capacitance change because of the micropyramids and electrode configuration is identified. After comparing the different designs of MPF sensors, it is confirmed that polydimethylsiloxane micropyramids covered with the highly compliant Ecoflex show the highest sensitivity. The MPF sensor shows the sensitivity of 685 mV N−1 in a range between 50 and 400 mN. MPF sensors are attached to the wrist and neck to measure pulse pressure signals. Using the pulse pressure signals and linear regression, blood pressures are estimated and compared with the values measured with a commercial cuff device.

A Review of Skin-Wearable Sensors for Non-Invasive Health Monitoring Applications

“…Piezoelectricity occurs in certain materials (such as crystal, ceramics, and piezoelectric or electroactive films) that accumulate electrical charge in response to an applied mechanical force, changing the distance between dipoles of the material [ 182 , 185 ]. The ability of a material to convert mechanical force to an electrical charge can be described as , the piezoelectric coefficient: where is the charge density and is the applied force [ 186 ].…”

Self-Reinforced Piezoelectric Response of an Electroluminescent Film for the Dual-Channel Signal Monitoring of Damaged Areas

“…The health monitoring system for polymeric structural components is an engineering monitoring system designed for real-time observation, reporting, and early warning of structural damage. , This methodology is instrumental in devising field assessment strategies for nondestructive damage monitoring across a multitude of domains, encompassing aviation, aerospace, marine sciences, and microdevices. − In recent years, embedded sensing devices have been widely employed in damage-monitoring systems for data collection and monitoring. − These systems utilize a preset threshold value to detect changes in specific characteristics of the structural component, prompting maintenance measures to improve safety and extend the component’s service life. To ensure the longevity of polymeric structural components, it is vital to intervene at the initial stages of damage, typically when the component’s coating surface undergoes mechanical and chemical degradation due to external wear .…”

A Flexible and Wearable Visual Pressure Sensing System Based on Piezoresistive Sensors and Alternating Current Electroluminescence Devices

“…Piezoresistive senor, as one of the four basic pressure sensors (piezoresis tive, [12][13][14] capacitance, [15][16][17] piezoelec tric, [18][19][20][21] and triboelec tric, [22][23][24][25] ) can change resistance with pressure, which provides the possibility to control the luminance of ACEL device by voltage division in AC circuit. Currently, microstructured piezoresistive sensors are widely reported due to their high sensitivity and low response time, such as micropillars, [26] micropyramids, [27,28] microdomes, [29,30] and abrasive structures, [31,32] etc.…”