A polyurea interface structure with dual dynamic bonds endowing composites with synchronous self-healing and thermal conductivity properties†

Abstract

Polymer-based thermal management materials in electronic devices suffer from molecular structure damage under long-term mechanical injury and temperature difference changes, which degrades performance. However, the construction of composites with self-repairing and heat dissipation properties is still a challenge to be solved. Herein, a dual-functional polyurea (D-PUA)-based self-healing thermal conductive composite (IPDI@GO_x/D-PUA) was prepared via in situ polymerization of isophorone diisocyanate modified GO (IPDI@GO), terephthalaldehyde, and polyetheramine. Based on the D-PUA chain established between graphene nanosheets, heat transmission at the inner interface of the composite was realized, and the self-healing performance was ensured via interchain hydrogen bonds and intrachain imine bonds. The in-plane thermal conductivity (κ_‖) of up to 2.7 W m⁻¹ K⁻¹ and the tensile strength of 17.5 MPa of IPDI@GO_12.5/D-PUA illustrated its structural advantages. Significantly, κ_‖ and stress self-healing efficiency of the composite were more than 90% after undergoing three self-healing processes of scratching, cutting and fragment remodeling. The integration of graphene into a polymer matrix with dynamic bonds to form an integrated composite provides a new idea for constructing high-performance heat management materials with dual-effect coupling for self-healing and thermal conductivity.