Ultraelastic Nanomembrane with Controllable Hotspots and Enhanced Photon Recovery for Single-Molecule Surface-Enhanced Raman Scattering

The controlled assembly of noble metal nanomaterials at water-oil interfaces holds significant potential for enhancing the sensitivity and stability of surface-enhanced Raman scattering (SERS) technology. However, developing highly efficient nanomaterial assembly techniques to create structures with controllable plasmonic hotspots and easily transferable functionalities remains a critical challenge. Herein, we propose a hydrophobic modification-enhanced float assembly strategy to fabricate an ultraelastic nanomembrane (UE-nanomembrane) by reducing adsorption kinetic barriers. Controlled hydrophobic modification of silver nanowires (AgNWs) prevents sedimentation loss during assembly, enables controllable embedding of AgNWs into elastomers, and yields a compact UE-nanomembrane with tailored hotspots, facile transferability, and high elasticity─even at elevated AgNWs loadings. The resulting UE-nanomembrane exhibits notable mechanical properties, including ∼1490% elongation, robust hydrophobic stability, and exceptional folding tolerance. For SERS applications, the continuous hydrophobic microdroplet lens system enhances laser focusing and photon recovery rates, achieving single-molecule-level detection of methylene blue (MB). The prestretch capture strategy efficiently directs analytes to hotspot regions, enabling rapid and sensitive quantitative assessment of MB concentration in aquatic products. This work introduces an innovative float assembly platform for engineering hotspots in ordered nanomaterial structures, providing a versatile and scalable SERS substrate design.