Dynamic Disulfide Bond‐Driven the Shape‐Adaptive Self‐Healing of Polyurethane Microcapsules

Abstract

Abstract The limited self‐healing capability of materials synthesized using conventional isocyanate‐based microcapsules as repair agents highlights the need for innovative microcapsule systems. In this study, a novel microcapsule (PU1) design is introduced that incorporates dynamic disulfide bonds, endowing the microcapsule walls with self‐healing properties. Additionally, a comparative analysis is performed with conventional microcapsules (PU2) synthesized using 1, 4‐butanediol. The prepared PU1 microcapsules exhibited a typical shell‐core structure, and the median particle size decreased with increasing stirring speed. The glass transition temperature ( T g ) of the prepared PU1 microcapsule is −53.2 °C, while that of the PU2 microcapsules is −45.0 °C. Moreover, after being placed at 60 °C for 24 h, the damaged PU1 microcapsules effectively self‐healed. In contrast, the PU2 microcapsules do not demonstrate significant self‐healing properties. Furthermore, elastomer films with the same chemical composition are prepared, and the tensile strength and the elongation at break of the PU1 elastomer are 7.3 MPa and 1450%, respectively, demonstrating excellent mechanical properties. This work provides a novel approach for preparing intrinsic self‐healing polyurethane microcapsules, which is expected to solve the issue of non‐repetitive healing in external self‐healing materials.