Preparation and properties of magnetic phase change film integrated with multi-functions of self-cleaning, anti-fog and air purification

The synergistic integration of anti-fogging and air purification functionalities represents an emerging frontier in sustainable indoor environmental management. Herein, novel submicron magnetic phase-change microcapsules (MP-FS/Ag) were prepared through a multi-step fabrication strategy combining Pickering emulsification, hydrolytic polycondensation, and radiation reduction method. The MP-FS/Ag microcapsules have an average size of 400 nm, and feature a paraffin core (62.0 % paraffin encapsulation ratio) encapsulated within a hierarchically structured organic-inorganic composite shell comprising Fe 3 O 4 nanoparticles, fibrous silica, polydopamine (PDA), and silver nanoparticles (AgNPs). They can be uniformly and stably dispersed in polyvinyl alcohol (PVA) to form a transparent PVA composite film with a surface contact angle of 11.8 o . The high hydrophilicity endowed by polydopamine and PVA enables the film to achieve anti-fogging and self-cleaning properties through accelerated diffusion and absorption of condensed water, and effective formaldehyde degradation (87 % removal in 150 min) was achieved via AgNPs-enabled photocatalysis. In fact, the efficient thermal regulation and collaborative photothermal effect (94.8 % solar-thermal conversion efficiency) of MP-FS/Ag also conducive to the superior anti-fogging performance. The strong PDA-PVA interfacial interactions and the hierarchical shell architecture consists of PDA and AgNPs can guarantees the long-term structural stability of the composite film. This multifunctional system establishes a new paradigm for smart environmental management in confined spaces (e.g., vehicles, greenhouses), while providing design insights for advanced anti-fog optical devices. The magnetic retrievability and solar-responsive features further enhance practical applicability in circular economy frameworks.