Construction of amide-bonded supramolecular multifunctional fillers towards boosted self-healing, thermal conductivity and dielectric properties

Multifunctional composites with rapid self-healing performance have been widely applied in various fields. However, different types of fillers result in decreased self-healing efficiency and present agglomeration and poor compatibility especially at high filler contents. Here, based on the different surface modifications of barium titanate (BT) and silicon carbide (SiC) and the amide-bond synergistic effects between these fillers, self-healing supramolecular composites with high filler contents (up to 30%) are reported, and exhibit high strength, dielectric and thermal-conduction properties. Modification significantly improves the dispersion of these fillers, and greatly enhances the coexistence and synergy between these fillers. This three-phase amide-bonded supramolecular composite exhibits a high tensile strength of 3.22 MPa compared to other self-healing materials such as self-healing hydrogels, a high dielectric constant of 23, a high thermal conductivity of 0.36 W m⁻¹ K⁻¹ and a superior self-healing efficiency of above 94%. These performances are ascribed to the formation of amide bonds between the amino groups in 3-aminopropyltriethoxysilane (KH550)-modified silicon carbide (SiC-NH₂) and the carboxyl groups in tartaric acid (TA)-modified barium titanate (BT-TA), which can provide efficient supramolecular interactions between different fillers, as well as more reversible hydrogen bonding for the matrix. This three-phase amide-bonded supramolecular composite provides an effective strategy to improve the self-healing properties of multifunctional composites, and will bring pioneering functions to electronic packaging materials, dielectric energy storage materials, environmental energy and other fields, which can open up broad application prospects.