Flexible Capacitive Pressure Sensor Based on a Double-Sided Microstructure Porous Dielectric Layer

Abstract

In the era of intelligent sensing, there is a huge demand for flexible pressure sensors. High sensitivity is the primary requirement for flexible pressure sensors, whereas pressure response range and resolution, which are also key parameters of sensors, are often ignored, resulting in limited applications of flexible pressure sensors. This paper reports a flexible capacitive pressure sensor based on a double-sided microstructure porous dielectric layer. First, a porous structure was developed in the polymer dielectric layer consisting of silicon rubber (SR)/NaCl/carbon black (CB) using the dissolution method, and then hemisphere microstructures were developed on both sides of the layer by adopting the template method. The synergistic effect of the hemispheric surface microstructure and porous internal structure improves the deformability of the dielectric layer, thus achieving high sensitivity (3.15 kPa−1), wide response range (0–200 kPa), and high resolution (i.e., the minimum pressure detected was 27 Pa). The proposed sensing unit and its array have been demonstrated to be effective in large-area pressure sensing and object recognition. The flexible capacitive pressure sensor developed in this paper is highly promising in applications of robot skin and intelligent prosthetic hands.

Flexible Capacitive Pressure Sensor with High Sensitivity and Wide Range Based on a Cheetah Leg Structure via 3D Printing

“…To prepare high-performance flexible pressure sensors, numerous researchers have dedicated their efforts to investigating materials that can be used in flexible sensors. The primary flexible materials that have been studied include silicone rubber, , poly­(dimethylsiloxane) (PDMS), , and hydrogels. , The aforementioned materials are highly flexible, enabling the preparation of nanometer-sized structures. With the use of these flexible materials, researchers can achieve more innovative structural patterns.…”

Bioinspired Engineering of Fillable Gradient Structure into Flexible Capacitive Pressure Sensor Toward Ultra‐High Sensitivity and Wide Working Range

“…Furthermore, we addressed the low compression characteristics of the structural patterns of the dielectric layer in the above study by designing fillable structures, and there is no significant hardening of the dielectric layer as the pressure of the filled structure increases. To date, various elastic dielectric substrates have been extensively studied for their dielectric properties on sensor performance, such as polydimethylsiloxane, [26][27][28][29][30] silicone rubber, [31] hydrogel, [32][33][34] and other super-elastic materials. Both structural and material level options are chosen to balance the contradiction between high sensitivity and a wide range of flexible sensors.…”

Flexible Microstructured Capacitive Pressure Sensors Using Laser Engraving and Graphitization from Natural Wood

“…Flexible pressure sensors are increasingly being paid more attention, because their flexibility, light weight, and stretching are crucial to a wide range of applications in surgical operation [ 1 , 2 , 3 , 4 ], moisture detection [ 5 , 6 , 7 , 8 , 9 , 10 ], human motion [ 11 , 12 , 13 , 14 ], and wearable devices [ 15 , 16 , 17 ], etc. According to various working mechanisms, flexible pressure sensors can be categorized by resistivity [ 10 , 18 , 19 ], capacitance [ 20 , 21 , 22 ], triboelectricity [ 23 ], and piezoelectricity [ 24 , 25 ]. Among them, capacitive flexible sensors have been studied extensively by researchers because of their simple structure, easy assembly, and wide range of applications [ 20 , 21 , 22 , 26 ].…”

“…According to various working mechanisms, flexible pressure sensors can be categorized by resistivity [ 10 , 18 , 19 ], capacitance [ 20 , 21 , 22 ], triboelectricity [ 23 ], and piezoelectricity [ 24 , 25 ]. Among them, capacitive flexible sensors have been studied extensively by researchers because of their simple structure, easy assembly, and wide range of applications [ 20 , 21 , 22 , 26 ]. A large number of microstructures comprising micropyramids, microdomes, semicylinders, porous structures, etc., have been applied for improving the sensitivity of capacitive pressure sensors [ 20 , 22 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”