Flexible sensors based on assembled carbon nanotubes

Abstract

Flexible sensors have attracted significant attention as they could be directly attached to/implanted into the body or incorporated into textiles to monitor human activities and give feedbacks for healthcare. A typical fabrication method is the direct use of intrinsically flexible active materials such as carbon nanotubes (CNTs). CNTs are generally assembled into aligned structures to extend their remarkable chemical, mechanical, and electrical properties to macroscopic scale to afford high sensing performances. In this review, we present the recent advance of CNT assemblies as electrodes or functional materials for flexible sensors. The realizations of aligned CNTs are firstly investigated. A variety of flexible sensors based on the aligned CNTs are then carefully explored, with an emphasis on understanding the working mechanism for their high sensing properties. The main attention is later paid to comparing two main categories of flexible sensors with fiber and film shapes. The remaining challenges are finally highlighted to offer some insights for future study.

Development of catalysts and electrolyzers toward industrial-scale CO2electroreduction

“…The supports with high surface area, high conductivity, and catalytic inertness are conducive, as otherwise, they could interfere with the CO 2 RR. [40][41][42] Zhao et al 37 dispersed CoPc on CNTs via p-p stacking interactions, achieving an FE CO of 97% at 200 mA cm À2 . In addition, the molecularly dispersed CoPc on CNTs presented higher catalytic activity and stability than the aggregated one.…”

Cross-Talk Signal Free Recyclable Thermoplastic Polyurethane/Graphene-Based Strain and Pressure Sensor for Monitoring Human Motions

“…This causes difficulty to predict whether the signal so generated originated from which external impulse and is commonly referred to as the cross-talk of the signals of the sensors. In terms of the filler, graphene, − carbon nanotubes, ,− silver nanowires, − carbon black, − and hybrid nanostructures − are commonly used as the functional sensing component. However, among the different classes of the fillers that are being used for sensing, graphene has gained a great deal of attention as a potentially useful candidate for the development of new-generation electronic devices. , Under strain, the graphene alters its electronic structure, which in turn will cause a significant shift in the resistance of the material. ,, This ability of graphene along with the superior mechanical and electrical properties, carrier mobility, and ultra-translucency paved the way for graphene to be used in high-sensitivity strain sensors. − …”

Bioinspired Flexible Wearable Sensor with High Self-Cleaning and Antibacterial Performance for Human Motion Sensing

“…Superhydrophobic materials are developed through in-depth observation and exploration of the microsurface structures of the “lotus effect” in nature, and possess hydrophobic, self-cleaning, and antibacterial characteristics. − The integration of superhydrophobic materials with flexible electronic devices in superhydrophobic flexible strain sensors has greatly overcome the limitations of sensor performance in various environments, particularly in applications related to human motion monitoring. Graphene, carbon nanotubes, carbon black, and Ag nanowires are frequently utilized in the construction of superhydrophobic micro/nano rough structures and conductive networks. − These nanomaterials possess high electrical conductivity and adhesion with the substrate while providing rough structures for superhydrophobicity. Among the above nanomaterials, carbon black is particularly suitable for the fabrication of hydrophobic wearable sensors due to its low cost and excellent electrical conductivity …”