Polydopamine‐modified black phosphorus/microcapsule composite material used to enhance the solar thermal conversion and self‐healing performance of SBS modified asphalt

Abstract

This study developed UV‐responsive microcapsules to enhance the self‐healing properties of asphalt, addressing the limitations of low survival rates and single‐release mechanisms in current encapsulated rejuvenators. The microcapsules, featuring a urea‐formaldehyde shell embedded with polydopamine‐coated black phosphorus nanosheets (BP/DA) and microalgae bio‐oil as the core, can convert solar energy into thermal energy, promoting proactive self‐healing in asphalt materials. BP/DA expands the microcapsules' light absorption range, enhancing their photothermal conversion efficiency. When incorporated into styrene‐butadiene‐styrene (SBS)‐modified asphalt at a 1.5% dosage, the microcapsules (BP/DA/MC) improved the mechanical properties: ductility increased by 13.7%, softening point rose by 2%, and penetration decreased by 3.3%. The storage modulus (G′) at 46 and 64°C increased by 35.9% and 24.3%, respectively, compared to SBS asphalt. Additionally, the ductility self‐healing rate of BP/DA/MC/SBS asphalt improved by 209.7%, with a healing index (HI) of 78.16%. The microcapsules also demonstrated excellent photothermal conversion, increasing the asphalt's temperature by 22.6% under identical lighting conditions. This research offers a new method for developing intelligent self‐healing asphalt with multi‐mechanism activation, providing theoretical support for future third‐generation microcapsule‐based asphalt with remote‐controlled release and activation response.