Design of Flexible Pressure Sensor Based on Conical Microstructure PDMS-Bilayer Graphene

Abstract

As a new material, graphene shows excellent properties in mechanics, electricity, optics, and so on, which makes it widely concerned by people. At present, it is difficult for graphene pressure sensor to meet both high sensitivity and large pressure detection range at the same time. Therefore, it is highly desirable to produce flexible pressure sensors with sufficient sensitivity in a wide working range and with simple process. Herein, a relatively high flexible pressure sensor based on piezoresistivity is presented by combining the conical microstructure polydimethylsiloxane (PDMS) with bilayer graphene together. The piezoresistive material (bilayer graphene) attached to the flexible substrate can convert the local deformation caused by the vertical force into the change of resistance. Results show that the pressure sensor based on conical microstructure PDMS-bilayer graphene can operate at a pressure range of 20 kPa while maintaining a sensitivity of 0.122 ± 0.002 kPa−1 (0–5 kPa) and 0.077 ± 0.002 kPa−1 (5–20 kPa), respectively. The response time of the sensor is about 70 ms. In addition to the high sensitivity of the pressure sensor, it also has excellent reproducibility at different pressure and temperature. The pressure sensor based on conical microstructure PDMS-bilayer graphene can sense the motion of joint well when the index finger is bent, which makes it possible to be applied in electronic skin, flexible electronic devices, and other fields.

Applications of Graphene-Based Materials in Sensors: A Review

“…The double-layer graphene material makes the resistance of the sensor change significantly even under slight pressure. The conical microstructure PDMS substrate can improve the sensitivity of the sensor even when the deformation of the double-layer graphene sensor reaches saturation [58], as shown in the graph in Figure 2(c1). As a result of its high sensitivity and flexibility, the sensor can be applied to the real-time monitoring of human physiological signals.…”

“…pared by various processes with double-layer graphene to package the flexible pressure sensor [58]. The preparation process is shown in Figure 2b1.…”

“…The principle is that the piezoresistive effect of graphene material is used When under pressure, the C-C bond will differentiate or break, resulting in the change of resistivity of graphene film [59,60]. Since graphene film has excellent sensitivity and (b1) Preparation process of a sensor made of conical microstructure PDMS substrate and double-layer graphene [58]; (c1) Sensitivity curve of the sensor with and without conical microstructure [58]; (d1) Structure and enlarged details of electronic skin [59]; (e1) Size and photos of electronic skin [59].…”

“…Micromachines 2022, 13, 184 7 of 14 Some researchers improved the sensitivity based on a wide detection range and designed a PDMS double-layer graphene flexible pressure sensor with a conical microstructure [58]. The designer combines the conical microstructure PDMS substrate prepared by various processes with double-layer graphene to package the flexible pressure sensor [58]. The preparation process is shown in Figure 2(b1).…”

Fabrication of Suspended PMMA-Graphene Membrane for High Sensitivity LC-MEMS Pressure Sensor

“…These properties make the graphene membrane a promising material for the freestanding membrane, which can be applied as pressure sensors. Generally, graphene is always used with polymers such as PMMA or PDMS as a holder to allow it to remain suspended and subsequently form a freestanding graphene membrane [3][4][5]14,15].…”