A self-healing flexible sensor based on silicone rubber with synergistic effect of coordination and hydrogen bonds

Abstract

With the development of society, silicone rubber-based flexible sensors are frequently used in our daily life, such as monitoring people's physical health, tracking movement and activities, and improving rehabilitation processes. However, high-frequency use can also compromise the material structure and even impair the service life of the product. In this study, a novel type of self-healing flexible sensing material, PBDMS/PDMS/mMWCNTs, was prepared by first preparing polyborosiloxane (PBDMS) with boric acid and hydroxyl silicone oil, and then mixing it with 107 room temperature curing silicone rubber (PDMS) as a matrix and using silane coupling agent KH560 modified multi-walled carbon nanotubes (mMWCNTs) as fillers. PBDMS/PDMS/mMWCNT was constructed to form a dynamic crosslinked network, resulting in a high self-healing efficiency (up to 80% in 4 h at room temperature). mMWCNTs, on the other hand, reinforced the mechanical properties (tensile strength of 0.46 MPa and elongation at break of 120%) better than the most commonly used reinforcing agent in the industry, SiO₂ nanoparticles. At the same time, mMWCNTs dropped on both ends of the surface of the substrate, and the internal network formed a ‘sandwiched’ structure, which can endow the composite with excellent thermal conductivity and electrical conductivity.