Highly Stretchable, Soft, Low-Hysteresis, and Self-Healable Ionic Conductive Elastomers Enabled by Long, Functional Cross-Linkers

Herein, a novel strategy has been developed for the preparation of high-performance conductive elastomers featuring long functional polymer cross-linkers. The macromolecular cross-linkers containing multi boronic ester bonds in the backbone were designed via thiol/acrylate reactions between poly(ethylene glycol) diacrylate (PEGDA) and a dithiol-containing boronic ester (BDB). The obtained PEG–BDB was copolymerized with n-butyl acrylate (n-BA) to provide PBA/PEG–BDB elastomers. The resultant elastomers exhibit combined desirable properties of high stretchability, low Young's modulus, low hysteresis, and self-healing performance, simultaneously. To demonstrate their practical applications, sensors based on PBA/PEG–BDB were successfully attached onto diverse joints (wrist, elbow, and finger) of the puppet for real-time motion detection. What is more, the elastomer sensors could well recognize other human activities like writing. This work offers a new design strategy for flexible sensors by optimizing the cross-linked dimension with long functional polymer chains as cross-linkers.