Highly Ordered 3D Porous Graphene Sponge for Wearable Piezoresistive Pressure Sensor Applications

Abstract

Wearable sensors with excellent flexibility and sensitivity have emerged as a promising field for healthcare, electronic skin, and so forth. Three‐dimensional (3D) graphene sponges (GS) have emerged as high‐performance piezoresistive sensors; however, problems, such as limited flexibility, high cost, and low sensitivity, remain. Meanwhile, device‐level wearable pressure sensors with GS have rarely been demonstrated. In this work, highly ordered 3D porous graphene sponges (OPGSs) were first successfully prepared and controlled through an emulsion method, and then a device‐level wearable pressure sensor with high flexibility and sensitivity was assembled with a gold electrode and polydimethylsiloxane into a reliable package. The pH values were carefully controlled to form a stable emulsion and the OPGSs showed a highly ordered 3D structure with ultralow density, high porosity, and conductivity; this resulted in a gauge factor of 0.79–1.46, with 50 % compression strain and excellent long‐term reproducibility over 500 cycles of compression–relaxation. Moreover, the well‐packaged pressure sensor devices exhibited ultrahigh sensitivity to detect human motions, such as wrist bending, elbow bending, finger bending, and palm flexing. Thus, the developed pressure sensors exhibited great potential in the fields of human‐interactive applications, biomechanical systems, electronic skin, and so forth.

From 2D Graphene Nanosheets to 3D Graphene‐based Macrostructures

“…By modifying the size of the metal‐based nanoparticles, the resulting pore size within the 3D GBMs was modified. Microemulsions can also be efficiently used to prepare 3D GBMs of controlled pore size by adjusting the microemulsion droplet size (GO/cyclohexane ratio) and the pH . In a comparable approach, polystyrene (PS) charged nanobeads were used to control the size of the internal porosity of GA…”

Preparation of Bamboo-Like Carbon Nanotube Loaded Piezoresistive Polyurethane-Silicone Rubber Composite

“…Various carbon forms such as graphene, graphene oxide, multiwalled carbon nanotubes, and carbon black have already been used to make piezoresistive PU-silicone rubber composites for sensor development [ 18 , 19 , 20 , 21 , 22 , 23 , 65 ]. The carbon content in the present composites is very low (0.13–0.43 wt %).…”

“…It is essential to select proper materials with unique structures to prepare FPPSs with specific functions. Carbonaceous nanofillers such as carbon nanotubes (CNTs) [ 19 ], graphene [ 20 , 21 ], and carbon black [ 22 , 23 ] have been the focus of attention in the field of sensing materials development. The remarkable electrical conductivity and nanostructured fibrous appearance of carbon nanotubes (CNTs) makes them more than suitable for application as additives in pressure sensors [ 24 ].…”

Waterproof, thin, high-performance pressure sensors-hand drawing for underwater wearable applications

“…For piezoresistive-type, the sensors include several layers, the most important being two electrode layers separated by a low-conductive thin layer [30][31][32][33]. Herein, the resistance changes predominantly as a result of the change in the contact resistance with pressing.…”