ABSTRACT
Conductive hydrogels are 3D network structures showing high water content, flexibility, softness, or low elastic modulus along with electrical properties. Those characteristics make them excellent candidates with high potential applicability in flexible (bio)electronics like energy storage devices, (bio)sensors, drug delivery systems, actuators, or tissue engineering scaffolds. Imparting ionic/electronic conductivity across the hydrogel network has been achieved following different strategies: 1) Hydrogels containing ionized groups and the corresponding counter ions, 2) hydrogels made of intrinsically conducting polymers, or 3) by incorporating electrically conductive nanomaterials like metallic nanoparticles or carbon nanomaterials. Thus, the versatility in the chemical composition, the large number in synthetic routes, and the easy functionalization have allowed the development of a large number of CHs with successful applicability in fields like biomedicine, energy, catalysis, or robotics. The objective of this chapter is to provide an overview of the origin of electrical conductivity in hydrogels, the synthesis, properties, and potential application of different types of CHs.
