Preparation and performance analysis of dopamine hydrochloride functionalized E-51@MPF/SiO2 double-wall microcapsules for microcracks self-healing in cement-based materials

With the widespread application of cement-based materials, the self-healing problem of microcracks has become increasingly prominent. Self-healing microcapsule technology has received widespread attention due to its excellent healing properties. However, traditional single-walled microcapsules have a series of defects in the actual application process. To better solve this problem, this study used the method of secondary wall construction to prepare dopamine hydrochloride functionalized E-51@MPF/SiO2 double-walled self-healing microcapsules. By combining in situ polymerization and the sol-gel method, based on single-walled MPF, polydopamine-loaded nano-SiO2 particles are introduced to form a double-layer coating structure. Subsequently, a series of microcharacterization experiments were carried out to analyze in detail the morphology, functional groups, particle size, and thermal stability of the functionalized double-walled microcapsules. A uniaxial compression experiment was performed to verify the healing properties of the microcapsules. The results show that dopamine hydrochloride-functionalized double-walled self-healing microcapsules have good compactness, temperature resistance, and healing properties and have excellent particle size. To further analyze the microscopic synthesis mechanism, molecular dynamics simulation was used to elaborate on the two angles of mean square displacement and density distribution. This research innovated self-healing microcapsule technology and improved the safety of cement-based materials in the application process.