Mechanically robust and recyclable siloxane elastomers enabled by adjustable dynamic polymer networks for electronic skin

Abstract

Siloxane elastomers as substrate materials have recently attracted much interest in the applications of flexible electronics. Nevertheless, excellent mechanical properties, self-healing properties and recyclability can rarely be satisfied with single material simultaneously. In this study, multistrength hydrogen bonds and dynamic disulfide bonds were introduced into the siloxane to achieve high stretchability, good mechanical strength, comparative self-healing capacity and excellent recyclability. By adjusting the ratio of the two types of hydrogen bonding networks, the prepared elastomers exhibit tunable mechanical properties, stretchability, toughness and a coordinated self-healing efficiency of 25–80%. Benefiting from the aromatic disulfide, the siloxane elastomer exhibits significant improvement in tensile strength of ∼4.67 MPa, tensile strain of ∼1086% and toughness of ∼27.36 MJ m−3 with 75% healing efficiency. Furthermore, a self-healing flexible bifunctional sensor was constructed by encapsulating liquid metal alloy between the elastomers layers to detect the pressure and multiple human motions.