Piezoresistive Pressure Sensor Based on a Conductive 3D Sponge Network for Motion Sensing and Human–Machine Interface

Abstract

Flexible sensors have attracted increasing attention owing to their important applications in human activity monitoring, medical diagnosis, and human–machine interaction. However, the rational design of low-cost sensors with desirable properties (e.g., high sensitivity and excellent stability) and extended applications is still a great challenge. Herein, a simple and cost-effective strategy is reported by immersing polyurethane (PU) sponge in graphene oxide solution followed by in situ chemical reduction to construct a reduced graphene oxide (RGO)-wrapped PU sponge sensor. Ascribed to the excellent compressive resilience of PU sponge and an electrically conductive RGO layer, the constructed flexible sensor exhibits satisfactory sensing performance with high sensitivity (17.65 kPa–1) in a low-load range (0–3.2 kPa), a wide compression strain range (0–80%), and reliable stability (8000 cycles). In addition, these sensors can be successfully applied to monitor human movements and identify the weight of objects. Through the use of a sensor array integrated with a signal acquisition circuit, the reasonably designed sensors can realize tactile feedback via mapping real-time spatial distribution of pressure in complicated tasks and show potential applications in flexible electronic pianos, electronic skin, and remote real-time control of home electronics.

Synergy of Organic/Inorganic and Inner/Outer Cooperative Conductive Networks in Polydimethylsiloxane-Based Porous Foam on High-Performance Flexible Sensors

“…To further validate the stability of the cooperative conductive network in the inner and outer layers, the PP@MWCNTs/PDMS sensor exhibited excellent long-term cyclic stability through 5000 cycles of loading and unloading tests under a pressure of 6 kPa (Figure f). Compared with the reported composite foams loaded with conductive fillers in recent years (Table S2), PP@MWCNTs/PDMS exhibited excellent resistive sensitivity and detection range (Figure g). ,,,− …”

“…7 Among them, resistive-based flexible sensors can produce obvious response signals to various forces, including compression, torsion, and stretching, and they possess advantages such as simple structure, low cost, and convenient electrical signal processing. 8 With the rapid development of new active electronic materials, the rational structural configuration of conductive materials such as carbon-based nanomaterials, conjugated conductive polymers, and metal nanomaterials with flexible polymer matrices is one of the important ways to achieve high-performance flexible strain sensors. 9−11 In terms of rational structural configuration, the key is to select the appropriate nanomaterials and polymer matrices and achieve effective interface interactions between them.…”

Superhydrophobic and Stretchable Carbon Nanotube/Thermoplastic Urethane-Based Strain Sensor for Human Motion Detection

“…10 The composites of polymer/conductive material with good flexibility, a large tensile degree, and simple preparation cost have become popular for the production of flexible strain sensors. 11,12 The main conductive materials used include carbon black, 13 carbon nanotubes (CNTs), 14 reduced graphene oxide, 15 MXene, 16 etc. Carbon materials are commonly used in the preparation of flexible strain sensors because of their controllable micro/nanostructures, excellent conductivity, and chemical stability.…”

“…The composites of polymer/conductive material with good flexibility, a large tensile degree, and simple preparation cost have become popular for the production of flexible strain sensors. , The main conductive materials used include carbon black, carbon nanotubes (CNTs), reduced graphene oxide, MXene, etc. Carbon materials are commonly used in the preparation of flexible strain sensors because of their controllable micro/nanostructures, excellent conductivity, and chemical stability. , On the other hand, the electrostatic spinning process, which can easily control the weight, specific surface area, and pore structure of a polymer nanofiber film, has attracted much attention for the fabrication of strain sensors. , The obtained flexible strain sensor can maintain an excellent sensing performance under large strain conditions by using an electrospinning process to prepare polymer nanofibers and construct a conductive layer on the surface .…”

Highly Sensitive Capacitive Fiber Pressure Sensors Enabled by Electrode and Dielectric Layer Regulation

“…Soft pressure sensors, as an important part of flexible electronics, are in increasing demand in the fields of artificial intelligence, , human–machine interface, , and health monitoring. , As an indispensable item in daily life, textile is the ideal choice for electronic skin. − Fiber is the smallest component of textiles, and the development of one-dimensional (1D) electronic materials can give electronic skin more freedom. , In addition, fiber electronics are also the cornerstone of two-dimensional (2D) textile electronic devices and three-dimensional (3D) smart clothing. , Therefore, the functional development of electronic skin at the 1D fiber level is a necessary research trend.…”