Tough, self-healable and conductive elastomers based on freezing-thawing strategy

Flexible conductive elastomers with excellent mechanical properties and body-temperature self-healing are highly desirable for wearable electronics. However, it is still a challenge to develop such elastomers because mechanical strength and healing efficiency are contradictory and are difficult to realize the concurrent optimization. Herein, we design stretchable conductive composites by combining tough self-healable elastomeric matrix and in-situ formed polypyrrole network. The elastomeric matrix, fabricated by copolymerization of N-isopropylacrylamide and 2-methoxyethylacrylate, displays superior mechanical strength (8.2 MPa) and high body-temperature healing efficiency (94%), enabled by combination of the dynamic hydrogen bonding and microphase separation structures from freezing-thawing treatment. The resultant conductive elastomers exhibit excellent strength of 7.4 MPa, high stretchability of 410%, good electrical conductivity of 12.5 S/m and over 70% body-temperature healing efficiency. Moreover, it is revealed that the conductive elastomers could be used as strain sensors due to high sensitivity of stretchability.