Fabrication of Gyroid‐Structured Metal/Semiconductor Nanoscaffolds with Ultrasensitive SERS Detection via Block Copolymer Templating

Surface‐enhanced Raman scattering (SERS) is a label‐free and powerful technique for monitoring dynamic molecular processes with high sensitivity and reproducibility. SERS has diverse applications in medicine, molecular science, biology, and chemical sensing. In this study, a template‐based approach to create an ultrasensitive SERS‐active substrate is proposed which involves combining nanostructured semiconductors and noble metals. A nanoporous polymer obtained from hydrolyzed gyroid‐forming polystyrene‐block‐poly(l‐lactide) (i.e., PS‐b‐PLLA) is used as a template for Ag reduction and TiO2 sol–gel reaction. After calcination to remove the polymeric template, TiO2 nanoscaffolds appear as self‐supporting 3D nanoobjects with homogeneously and closely distributed Ag nanoparticles, providing a high density of regions with intense local field enhancement (hotspots). Rhodamine 6G molecules are used as probe molecules to demonstrate the SERS performance, revealing a markedly high average enhancement factor of up to 1014. The intrinsic photocatalytic properties of TiO2 can degrade target organic chemicals for the self‐cleaning and reproduction of SERS‐active substrates. Moreover, a simple hydrazine reduction‐based approach is applied for the formation of regenerated Ag/TiO2 nanoscaffolds to reduce the use of Ag‐based SERS‐active substrates, decreasing the costs associated with relevant industrial processes. A template‐based approach is proposed to create an ultrasensitive surface‐enhanced Raman scattering (SERS)‐active substrate that involves combining nanostructured semiconductors and noble metals. Nanoporous polymers obtained from hydrolyzed gyroid‐forming polystyrene‐block‐poly(l‐lactide) are used as templates for Ag reduction and TiO2 sol–gel reaction. After calcination to remove the polymeric templates, gyroid‐structured Ag/TiO2 nanoscaffolds are generated, revealing a high enhancement factor of up to 1014.