Stretchable and self-healing ionic conductive elastomer for multifunctional 3D printable sensor

Abstract

Soft ionic conductors (ICs) such as hydrogels and ionogels have attracted extensive attention as they are promising candidates as the key components used in flexible electronic devices. Nonetheless, hydrogels and ionogel-based materials reported by previous studies usually exhibit prominent problems, such as solvent leakage and evaporation, limiting their application in complex environment. In this work, solid-state conductive ionogels (SCIg) composed of long-chain copolymer networks without any volatile liquids were designed and prepared. The dynamic non-covalent bonds ensure its long-term stable signal monitoring as a sensor. The SCIg shows extraordinary comprehensive properties, including admirable tensile strength (0.97 MPa) under large deformations (λ = 26.6 tensile stretch), promising conductivity (56.1 mS m−1) and surprising self-healing efficiency (>95 %). Notably, the SCIgs solved a well-established problem in ionogels, namely the conflict of ionic conductivity versus mechanical properties. Moreover, a series of ionoelastomers based on the SCIg were further exploited as a resistance-type sensor, capacitive-type sensor and multifunctional electronic skins capable of detecting a variety of mechanical signals. The sensors deliver splendid long-term stability with signal responses. Meanwhile, the obtained SCIgs exhibit high efficiency ultraviolet (UV) curable 3D printability, enabling the bulk production of microcircuits with 130 μm diameter in a transitory time. This work shows that the developed SCIg presents great application potential in the fields of electronic skin, physiological signal detection and human–machine interface.