Chengdu Institute of Biology progresses in the study of self-healing conductive elastomers

Organic conductive materials have both metallic conductivity and organic materials as compliant and processable, and have broad application prospects in military, energy, and biochemical sensors. However, during its manufacture and use, under the influence of environmental factors such as light, heat, and mechanical forces, localized damage or micro-cracks are easily generated, resulting in component failures and even causing the entire system to fail and fail. In recent years, based on the concept of bio-injury healing, the study of functional materials with self-healing characteristics has become the focus of scholars' attention. However, at present, research on self-healing conductive materials is still at a preliminary stage.

Li Bangjing, a researcher at the Chengdu Institute of Biology, Chinese Academy of Sciences, has long devoted himself to the study of functional self-healing materials based on the recognition of cyclodextrins. Carbon nanotubes (SWCNT) with surface grafted cyclodextrin (β-CD) and hydroxyethyl methacrylate (HEMA) containing guest adamantyl group (Ad) were assembled, and then the inclusion compound and HEMA alone were assembled. The body was copolymerized in a specific solvent in a certain proportion, and a conductive elastic material having a self-healing function was successfully prepared.

The study shows that through the recognition of host-guest between the cyclodextrin and the guest group, the carbon nanotubes and HEMA form a cross-linked three-dimensional network structure, and the material exhibits good elasticity and mechanical properties. As the carbon nanotubes are densely packed to form a conductive path, the elastic material has a good electrical conductivity. When the material is damaged, there are a large number of free host-guest groups at the fracture surface. After the two sections are re-contacted, the host-guest interaction can occur, leading to self-healing of the material. And, after three cycles of self-healing, the mechanical properties of the material recovered more than 50%, and the electrical conductivity recovered more than 90%. In addition, the material has potential application value in the field of humidity sensing and proximity sensing. Related articles were published in the international magazine Angewandte Chemie International Edition (VIP paper).