Simultaneously achieving high strength, thermal resistance and high self‐healing efficiency for polyacrylate coating by constructing a Diels–Alder reversible covalent structure with multi‐maleimide terminated hyperbranched polysiloxane

Abstract It is difficult for the self‐healing polyacrylate coatings reported so far to simultaneously achieve high mechanical strength and high self‐healing efficiency within a short healing time. Herein, derived from multi‐maleimide terminated hyperbranched polysiloxane, linear polyacrylate with furan‐containing side chain and polydopamine particles (photothermal conversion agent), a new kind of polyacrylate coating (HPA) with a strong and flexible crosslinking network was developed, which simultaneously shows high mechanical strength and high self‐healing efficiency within a short time. With 0.3 wt% polydopamine particles in HPA, the resulting coating (HPA3) has the highest toughness (2.63 ± 0.10 MPa) with 12.9 ± 0.7 MPa tensile strength and 23.9% ± 1.6% elongation at break; in addition, the self‐healing efficiency of HPA3 is over 87.6% after only 2.5 min of near‐infrared laser irradiation, overcoming intractable problems in developing self‐healing polyacrylate coatings. A study of the mechanism behind these outstanding performances of the HPA system reveals that the reversible covalent crosslinking formed by multi‐maleimide terminated hyperbranched polysiloxane is the necessary and crucial factor for simultaneously achieving high mechanical strength and high self‐healing efficiency in a short time. © 2019 Society of Chemical Industry