Efficient Enrichment and Self-Assembly of Hybrid Nanoparticles into Removable and Magnetic SERS Substrates for Sensitive Detection of Environmental Pollutants.

A structure consisting of a low surface energy substrate and low surface tension liquid is designed and prepared by taking advantage of perfluorinated fluid infusion into the porous Teflon membrane. This slippery platform allows efficient enrichment and self-assembly of hybrid nanoparticles and the assembled structure can be detached from the membrane. A macroscale superlattice array of Au nanorods doped with magnetic Fe3O4 nanoparticles is obtained by suppressing the outward capillary flow and coffee-ring effect during evaporative self-assembly. In SERS (surface enhanced Raman scattering) detection of environmental pollutants including thiram, diquat and polycyclic aromatic hydrocarbons, the removable plasmonic superlattice array with magnetic properties enables rapid separation of analytes from the solution resulting in excellent sensitivity and detection limits down to the nanomolar level. The self-assembly strategy shows great potential in the fabrication of removable 3D plasmonic superlattice arrays for SERS detections.