A Multifunctional Surface for Microplastic Trapping, SERS‐Based Molecular Sensing, and PFAS Breakdown Through Microdroplet Deposition

ABSTRACT Microplastics (MPs) and per‐ and polyfluoroalkyl substances (PFAS) co‐occur in natural and drinking waters, where they persist, accumulate, and pose risks to ecological and human health. Their mitigation demands integrated detection and remediation beyond single‐function platforms. Here, we report Ag@TiO 2 nanobrushes (NBs), fabricated entirely by ambient charged microdroplet deposition, as a unified substrate for MP capture, SERS‐based sensing, and photocatalytic PFAS degradation. In a two‐step electrospray process, 1D Ag nanowire arrays (Ag NBs) were grown over large areas and overcoated with TiO 2 . During overcoating, a Marangoni‐type capillary rearrangement drives Ag nanoparticles to the wire periphery, yielding an Ag@TiO 2 architecture with a percolated plasmonic network in a photoactive TiO 2 scaffold. The 3D NB network traps MP beads, while dense electromagnetic 3D hotspots enable SERS detection of Rhodamine 6G (LOD ∼38 fM; EF ∼6 × 10 7 ) and 1 µm polystyrene beads (LOD ∼31.6 ng mL −1 ; EF ∼ 10 5 ) across DI, tap, and simulated seawater. The unmodified substrate drives photocatalytic degradation of perfluorooctanoic acid under ambient sunlight, confirmed by mass spectrometry. This is the first fully electrosprayed platform, integrating MP trapping, femtomolar‐level SERS detection, and PFAS photoremediation, thereby demonstrating ambient charged microdroplets as a scalable route to multifunctional nanostructures for water monitoring and remediation.