The Soft-Strain Effect Enabled High-Performance Flexible Pressure Sensor and Its Application in Monitoring Pulse Waves

Abstract

Flexible and wearable pressure sensors attached to human skin are effective and convenient in accurate and real-time tracking of various physiological signals for disease diagnosis and health assessment. Conventional flexible pressure sensors are constructed using compressible dielectric or conductive layers, which are electrically sensitive to external mechanical stimulation. However, saturated deformation under large compression significantly restrains the detection range and sensitivity of such sensors. Here, we report a novel type of flexible pressure sensor to overcome the compression saturation of the sensing layer by soft-strain effect, enabling an ultra-high sensitivity of ~636 kPa −1 and a wide detection range from 0.1 kPa to 56 kPa. In addition, the cyclic loading-unloading test reveals the excellent stability of the sensor, which maintains its signal detection after 10,000 cycles of 10 kPa compression. The sensor is capable of monitoring arterial pulse waves from both deep tissue and distal parts, such as digital arteries and dorsal pedal arteries, which can be used for blood pressure estimation by pulse transit time at the same artery branch.

Application of Poisson’s ratio structures and decoupling algorithm for 3D force sensing

“…of the flexible sensitive unit, making it challenging to strike a balance between wide detection range and high sensitivity [8,9]. Thus it becomes a crucial pursuit to promote the sensitivity [10]. Secondly, many tactile sensors heavily depend on normal forces to make decisions, presenting a challenge for precise decision-making in emerging electronic skin (eskin) applications [11,12].…”

Arteriosclerosis Assessment Based on Single‐Point Fingertip Pulse Monitoring Using a Wearable Iontronic Sensor

“…Flexible pressure sensors can convert mechanical stimuli into electrical signals and have been widely used to detect arterial pulse waves in a continuous mode because flexible devices can be conformally laminated on human skins for long-term monitoring. [17,18] Although great efforts on the measurement of PWV have been made, [19] existing PWV acquisition based on flexible pressure sensors still uses a two-point method, for which two sensors detect pulse waves at different arterial locations (mostly joints) simultaneously. [20] This technology, however, suffers from two drawbacks.…”

Scalable Manufacturing of Large-Area Pressure Sensor Array for Sitting Posture Recognition in Real Time

“…However, the scalable manufacturing of large-area pressure sensors, especially highly integrated sensor arrays, using unconventional materials and device structures remains challenging, yet promising in novel and practical applications including the recognition and correction of sitting postures. The general strategies to realize a pressure sensor array typically include the photolithography technique, ,, laser writing, , or drop casting, ,, which comprises a relatively complex fabrication process. In addition, the sensing areas and sensitive elements are still limited, ,− which is an obstacle to the precise and accurate monitoring of external stimuli with large sizes or multiple positions.…”

“…Recently, physical and psychological problems caused by the sedentary lifestyle have recently received special attention. Flexible pressure sensing with array structures provides a non-invasive, seamless, and convenient approach with an intervention function to recognize the sitting postures and correct the wrong sitting states during sustained working or study periods. , Up to now, significant progress has been made in the development of flexible pressure sensors by exploring novel functional materials, − introducing unique microstructures, ,, and constructing unconventional device configurations − to enhance the collective sensing performance, such as high sensitivity over a wide pressure range, low detection limit, and fast response time . However, the scalable manufacturing of large-area pressure sensors, especially highly integrated sensor arrays, using unconventional materials and device structures remains challenging, yet promising in novel and practical applications including the recognition and correction of sitting postures.…”