ABSTRACT
Flexible and wearable sensing systems based on color-changing materials are attracting widespread attention on account of their applications. These sensors are used for monitoring personal and/or public vital signs, healthcare applications, the Internet of Things, the fabrication of intelligent robots, and human-machine interfaces. The color appearance of these sensing materials is owed to the incorporation of structural colors into hydrogels. These composites can be further employed as bulk, thin film coatings, fibers, or core-shell structures. In this chapter, color-based flexible and wearable sensors are introduced, the fundamental basics of color production in these sensors are discussed, and their structural composition and final applications are reviewed in detail. Finally, the challenges that these sensing materials are facing today, some solutions to overcome the issues, and the future perspectives of these materials are discussed.
