A Wearable Sensor Based on Gold Nanowires/Textile and Its Integrated Smart Glove for Motion Monitoring and Gesture Expression

Abstract

According to the sensing mechanism, pressure sensors can be divided into five types: piezoelectric, [1,2] piezoelectric resistivity, [3][4][5][6] capacitance, [7,8] triboelectric, [9,10] and transistor. [11] Piezoresistive sensors have attracted much attention in recent years due to their simple design, low manufacturing cost, good signal repeatability, low power consumption, low working voltage, and simple measurement scheme. [12][13][14][15][16][17][18] The elastic pressure sensor is usually composed of sensing material, substrate material, and electrode. The sensing material can be filled or coated on the substrate material to activate the conductive path. Under the external pressure, the contact area between the surface conductive elements increases significantly, resulting in a significant decrease in the path resistance or contact resistance. The change of resistance is due to the deformation of the microstructure under pressure, which leads to the change of the contact area. The traditional rigid material pressure sensor has been eliminated due to its poor reliability and low applicability. As an optional piezoresistive material, nanomaterials have been proved to be potential components of novel strain sensors with enhanced performance. High-performance sensor devices based on several typical nanostructures, such as carbon nanotubes [19,20] and graphene, have been developed. [21] However, the sensors based on these materials have some defects, such as complex manufacturing processes and unknown toxicity.Sensing material is the essential component of a pressure sensor. In terms of sensing materials, metal nanomaterials, as one of the most popular multifunctional conductive materials, have been widely used in chemistry, biomedical, optical, and other fields. [22] Specifically, gold nanowires (AuNWs) are a flexible filamentous structure in the nanoscale and behave like polymer chains because of their ultrathin nature (2 nm in width and >10 000 in aspect ratio). [23] AuNWs have the advantages of high chemical inertness, good biocompatibility, wide electrochemical window, high conductivity, and easy surface modification that depends on thiol gold chemistry. Zhang and co-workers reported a pulse monitoring sensor based on AuNWs and polyacrylamide

Design and Manufacture of Data Gloves for Rehabilitation Training and Gesture Recognition Based on Flexible Sensors

“…The direct contact sensor touches the surface of the skin and detects physical signs through electrical signals or chemically analyzes human sweat. Noncontact sensors are usually placed in some common wearable clothing and accessories [ 5 , 6 ] and are currently the main sensor type used in wearable devices. Embedded sensors will be implanted inside the human body to monitor the physiological information of human organs, joints, and other parts.…”

Comparison between Piezoelectric and Piezoresistive Wearable Gait Monitoring Techniques

“…For piezoresistive sensors, conductive polymers such as thermoplastic polyurethane (TPU) [ 13 ], fiber-reinforced polymer (RFP) [ 14 ], and Parylen-C polymer film [ 15 ] can be used to increase sensor flexibility. Mixtures of carbon nanotubes and metal particles [ 11 , 16 , 17 , 18 ] can improve the sensing range and sensitivity of the sensors. Metal liquids such as E-GaIn-based piezoresistive PSD sensors can detect shear stress [ 19 ].…”

“…The general types of conductive ink include carbon nanoparticles, metallic compounds, and metal nanoparticles [ 29 ]. In pressure sensors, carbon nanotubes and metallic compounds are most frequently applied [ 16 , 17 ]. On the one hand, the resistivity of metallic particles is relatively lower than that of conductive polymers [ 29 ], producing increased piezoresistivity.…”

“…They also have both metal and semiconductor properties, which indicates that they have many potential applications in PSD. Composites of carbon nanotubes and carbon black are often used as the sensing material in PSD sensors [ 16 , 17 ]. An example of this is the insole system devised by Jung et al [ 16 ].…”

“…Zhao et al [ 17 ] devised an Au/textile sensor system. Their sensor had two essential parts: substrate and sensing materials.…”