Sponge Graphene Aerogel Pressure Sensors with an Extremely Wide Operation Range for Human Recognition and Motion Detection

Abstract

Pressure sensors have been widely expected to be applied in wearable electronics for monitoring daily motions or healthcare information. Specifically, portable plantar pressure detection, which could enrich the gait information in customer-level application and enhance the dynamic precision in medical-level inspection, is essential in the wearable electronic field and has been widely demonstrated in reports. However, recently reported pressure sensors barely fit the demand of high-resolution plantar pressure detection due to the limited operation range: the pressure in some position of planta could be over 300 kPa in the standing state, not to mention the pressure in walking and running states. To satisfy the critical demand of plantar pressure detection, herein, we introduced a frameless self-assembled spongelike structure graphene aerogel and further developed a high-performance pressure sensor. The aerogel freeze-dried from a glycerin-decorated alginate/graphene hydrogel presents a sponge structure and helped the as-present pressure sensor to achieve an extremely wide operation range of up to 1000 kPa with high sensitivity, low detection limit, high durability, and rapid response time. Based on the extraordinary performance of the pressure sensor, we designed a high confidence portable plantar pressure phase monitoring system. This system could provide impressive plantar pressure information for recognition of different testers and detecting different daily motion states and even warning for possible slipping.

Widening the Sensing Range of Piezoresistive Composites by Constructing Multilevel Porous Structure

“…The force/pressure sensing range was extended by using the different elastic modulus of two porous structures. The resistivity change [31,34,36,[42][43][44] when subject to external force/pressure was realized by changing the inner contact state of conductive layers once being deformed. We used alternatively stacked PAN NF layers and Ag NW layers as a model structure.…”

“…Figure 6. Comparison of sensor sensitivity versus pressure range for flexible piezoresistive sensrs [31,34,36,[42][43][44]. …”

Multiwalled Carbon Nanotube/Graphite Powder Film for Wearable Pressure Sensors with High Sensing Performance

“…As research in the field of materials science has progressed, various nanomaterials with great mechanical and electrical characteristics have been used in the fabrication of piezoresistive sensors, including carbon black [ 7 , 8 ], graphene [ 9 , 10 ], silver nanowires [ 11 ], carbon nanotubes [ 12 ], and so on [ 13 ]. Among them, multiwalled carbon nanotubes (MWNTs) and graphite powder (Gp) have been demonstrated to be excellent candidates for flexible sensors due to their advantages, such as superior mechanical flexibility, stability, and electrical conductivity [ 14 , 15 ].…”

Protrusion Microstructure-Induced Sensitivity Enhancement for Zinc Oxide–Carbon Nanotube Flexible Pressure Sensors

“…For the past few years, flexible pressure sensors have been extensively applied in various fields, such as human–machine interfaces and electronic skins. − Thus far, in order to develop high-performance flexible pressure sensors, various pressure-sensing mechanisms (like piezoresistivity, capacitance, piezoelectricity, and triboelectricity) have been adopted. − In particular, piezoresistive sensors have numerous strengths such as high compatibility with a readout circuit, fast response, simple device structure, and excellent stability. − The sensing material plays a decisive role in the performance of piezoresistive pressure sensors. Carbon nanotubes (CNTs) have wide perspective applications in pressure sensors due to their superior mechanical and electrical properties. − However, a pure CNT sensor is still limited by its low sensitivity, which restrains its detection ability toward micropressure changes, such as a wrist pulse.…”