A novel MXene-based high-performance flexible pressure sensor for detection of human motion

Abstract

Flexible pressure sensors possess superior conformal ability, great flexibility, and strong biocompatibility than conventional silicon-based sensors, thereby widely used in electronic skin, wearable devices, and robotic tactile sensing, among other fields. However, flexible pressure sensors are still limited by many challenges related to extended linearity and high sensitivity. In this paper, MXene with a loose layered structure was employed to fabricate high-performance flexible piezoresistive sensors comprising PDMS film with cylindrical microstructure, multilayer Ti3C2Tx-MXene film, and interdigital electrodes. A cylindrical microstructured silicon wafer was designed and processed by deep silicon etching process, and PDMS flexible substrate was obtained by two inversions as the pressure sensing layer. The resulting flexible pressure sensor exhibited excellent performance in terms of excellent sensitivity up to 519 kPa-1 in the large detection range of 0-8 kPa coupled with great linearity, a response time of 62.7 ms, and a recovery time of 62.8 ms. The high sensitivity was associated with the compression of the interlayer spacing of multilayer MXene nanosheets. In addition, a single flexible pressure sensor and integrated array were utilized to detect the human physical signals and quantitative measurements of pressure distributions. Overall, these findings provided experimental verification for the design and manufacturing of highly sensitive and linear flexible pressure sensors.

Flexible and Stretchable Pressure Sensors: From Basic Principles to State-of-the-Art Applications

“…Biocompatibility (for biomedical applications): In applications involving direct contact with the human body, conductive materials should be biocompatible to ensure compatibility with biological tissues and minimize the risk of adverse reactions [ 88 ].…”

Linear Capacitive Pressure Sensor with Gradient Architecture through Laser Ablation on MWCNT/Ecoflex Film

“…In addition, several studies have already proved that increasing the dielectric constant can improve the sensitivity of sensors [32][33][34], which is usually achieved by mixing silicone rubber with conductive fillers (carbon nanotubes [33] and graphene [35]). Meanwhile, carbon nanotubes, due to their excellent conductivity and high aspect ratio, can significantly reduce dielectric permeation thresholds and have become the most commonly used conductive filler in research.…”

A soft tactile sensing array with high sensitivity based on MWCNTs-PDMS composite of hierarchically porous structure

“…In general, the sensing mechanisms of pressure sensor can be classified into four typical categories: piezoelectricity [7][8][9], piezo-resistance [10][11][12], optics [13][14][15] and capacitance [16][17][18]. Among these mechanisms, extensive researches on capacitive implementation have been widely carried out due to its fast response time, considerable stability, durability and economic efficiency.…”