Recent progress on fabrication of carbon nanotube-based flexible conductive networks for resistive-type strain sensors

Flexible resistive-type strain sensors are attracting wide attention due to their extensive potential applications. Carbon nanotubes (CNTs) with outstanding conductivity and mechanical properties can be assembled by various methods to form different conductive strain sensing networks within elastic polymers due to its nanoscale structure. Herein, the shapes of strain sensors are introduced including film, fiber and yarn, fabric, foams and gels. The various microstructures of CNT-based conductive networks are reviewed, such as uniform mixing, aligned structure, multilayered structure, porous structure, nanomesh structure, island-bridge structure, wavy structure, microarray structure, wrinkled structure, weaving structure. The lithographic processes, solution-based processing methods (such as dropping casting, spraying, ultrasonication, dip coating, sizing coating, layer-by-layer (LBL) assembly), chemical vapor deposition, printing technology (such as screen printing, inkjet printing, 3D printing) and electrospun technology were used to fabricate these conductive networks. The sensing performance and working mechanisms of these strain sensors with different conductive networks have been summarized and analyzed. Furthermore, their applications in the fields of personal healthcare, body motion detection, smart robot, human-machine interaction and structural health monitoring are reviewed. Finally, the existing challenges and prospective research directions are discussed. The CNT-based resistance-type strain sensors will be greatly promoted through innovations in integrating multidisciplinary technologies in future. @2021 Elseveier B V All rights reserved.

Automated summary

This paper introduces the structure, preparation methods, sensing performance, working mechanism, and application fields of flexible resistive-type strain sensors, while also discussing the challenges and future research directions.