The advent of conductive self-healing (CSH) hydrogels, a class of novel materials mimicking human skin, may change the trajectory of the industrial process because of their potential applications in soft robots, biomimetic prostheses, and health-monitoring systems. Here, the development of a mechanically and electrically self-healing hydrogel based on physically and chemically cross-linked networks is reported. The autonomous intrinsic self-healing of the hydrogel is attained through dynamic ionic interactions between carboxylic groups of poly(acrylic acid) and ferric ions. A covalent cross-linking is used to support the mechanical structure of the hydrogel. Establishing a fair balance between the chemical and physical cross-linking networks together with the conductive nanostructure of polypyrrole networks leads to a double network hydrogel with bulk conductivity, mechanical and electrical self-healing properties (100% mechanical recovery in 2 min), ultrastretchability (1500%), and pressure sensitivity. The practical potential of CSH hydrogels is further revealed by their application in human motion detection and their 3D-printing performance.

A strategy utilizing elastin peptide macroporous cryogels to build highly flexible scaffolds to load carbon nanotubes, polypyrrole, and iron oxide magnetic nanoparticles, is presented. This combines high elasticity, flexibility, shape memory property, and injectable property together with conductivity and/or magnetic responsive property. The network can afford 97.5% compressive strain with an excellent conductivity of 50.1 ± 2.9 S cm(-1) at 90% strain.