Multifunctional Mechanical Sensors for Versatile Physiological Signal Detection

Abstract

Recently, flexible and wearable mechanical sensors have attracted great attention because of their potential applications in monitoring various physiological signals. However, conventional mechanical sensors rarely have both pressure and strain sensing abilities that can meet the demands of both subtle and large human motion detection. Besides, the mechanical sensors with tunable sensitivity or measuring range are also essential for their practical applications. Herein, the graphene ink dip-coating method with merits of time saving, low cost, and large scale was used to fabricate the foam-structured graphene sensors with both pressure and strain sensing performance. Because of high elasticity of styrene butadiene rubber (SBR) substrates and stacked graphene flakes, the tunable mechanical sensors exhibit a high gauge factor (GF) and large measuring range for specific human motion detection. The pressure sensor shows a GF of 2.02 kPa −1 with a pressure range up to 172 kPa, and the strain sensor displays a GF of 250 with a strain range up to 86%. On the one hand, various detections of subtle vital signals with small strain change were demonstrated by the pressure sensor because of its flexibility and high sensitivity. On another hand, the strain sensor with large strain change shows excellent ability to detect various large human motions including the bending of neck, finger, wrist, and knee. Interestingly, both the pressure sensor and strain sensor exhibit great capability for recognizing 26 letters written by hand. The working mechanism based on the contact area variation was also investigated by the morphology evolution and resistance model. We suppose that the foam-structured graphene mechanical sensors would be promising in wearable electronics for human healthcare and activity monitoring in the future.

Highly Uniform and Low Hysteresis Piezoresistive Pressure Sensors Based on Chemical Grafting of Polypyrrole on Elastomer Template with Uniform Pore Size

“…Figure d is the Δ R / R 0 versus cycles plot for 1000 cycles of pressure at 50 kPa. The relative change in initial resistance after 1000 cycles (R 1000 −R 0 /R 0 ) was 2.7% (Figure e), which is a very small number compared to some of the piezoresistive sensors previously reported . Also, there are no noticeable cracks on the cross‐sectional image of the elastomer after 1000 cycles (see Figure S9 of the Supporting Information).…”

Self-Powered Sensors and Systems Based on Nanogenerators

“…The demand for motion sensors is increasing with the development of intelligent manufacturing, especially for mechanical motion sensors [59]. Current mechanical motion sensors are mainly limited by complex structures, high-costs, and difficulties in fabrication and assembling.…”

The effect of mechanical stimulation on the expression of apoptosis-related genes in cardiomyocytes

“…The relationship between mechanical stimulation and cardiomyocyte apoptosis has also been studied at the macroscopic scale. The adaptive remodeling of cardiomyocytes has been previously shown to occur in response to mechanical signals through study of the histomorphology and biomechanics of cardiomyocytes (Pang et al 2018). At the microscopic scale, cardiomyocytes are an important component of myocardial tissue and the primary focus of adaptive remodeling (Wang et al 2018b).…”