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

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.