Tough and self-healable carrageenan-based double network microgels enhanced physical hydrogels for strain sensor

Double network hydrogels (DN gels) demonstrate extremely high strength and toughness; however, conventional DN gels are fully chemically crosslinked, which are often softening and lack self-healing. Here, a new type of fully physical DN (P-DN) gels, that is, K + ions crosslinked κ -carrageenan (K + C) microgel (MG) composite hydrophobically crosslinked polyacrylamide (HPAAm) gels or K + C-MG/HPAAm gels, in which the HPAAm gel was physically crosslinked by hydrophobic interactions as well as topologically crosslinked by P-DN microgels, were prepared by a facile one-pot method. At the optimal condition, K + C-MG/HPAAm gel exhibited high strength (0.36 MPa) and high toughness (968 J/m 2 ). In addition, it can rapidly recover from softening and display good fatigue resistance. Notably, K + C-MG/HPAAm gel also demonstrated self-healing properties on account of its physical nature. Because there are anionic κ -carrageenan and KCl, K + C-MG/HPAAm gels are ionic conductive, which were used as strain sensors to monitor the human motions. We believe our K + C-MG/HPAAm gels provide a new insight in the field of DN gels. Graphical