Synergistic self-healing and antibacterial superhydrophobic coatings enabled by rational design of core-shell structured SiO2 microspheres

Superhydrophobic surfaces hold great promise as protective coatings for a wide variety of porous and hydrophilic substrates, yet their practical application is hindered by limited service lifespans, insufficient biofouling resistance, and concerns associated with fluorinated modifiers. This work reports fluorine-free superhydrophobic coatings that integrate biocidal and self-healing properties, developed through the design of mesoporous silicone oil core/SiO 2 shell microspheres. The SiO 2 microspheres were synthesized via a one-step miniemulsion-based soft template approach, and subsequently functionalized with Ag nanoparticles and 1-dodecanethiol. The resulting core-shell architecture performs dual structural and functional roles: (1) the covalently anchored Ag nanoparticles construct essential micro-to-nano hierarchical roughness while providing contact-killing bactericidal activity; (2) the coordinated 1-dodecanethiol molecules impart low-surface-tension alkyl chains while mitigating uncontrollable Ag leaching. Without employing a polymeric matrix, the coatings exhibit superhydrophobicity with a water contact angle above 155° and a sliding angle below 8°, together with broad-spectrum antibacterial performance. Moreover, owing to the intrinsic reservoir function of the core-shell microspheres, encapsulated dimethyl silicone oil enables recovery from chemical degradation (O 2 plasma etching) and thermal (60 °C, 24 h) healing of physical damage. Furthermore, the coatings also maintain superhydrophobicity under corrosive and abrasive conditions, and the damaged surfaces can be regenerated by thermal treatment. This work establishes a core-shell colloidal architecture for coupling wetting control, antibacterial functionality, and damage-responsive self-healing within a single interfacial system, providing a general strategy for designing durable multifunctional superhydrophobic coatings for porous materials, including stone-built heritage.