High-fidelity replica molding for large-area PMMA 3D nanostructures with high performance surface-enhanced Raman scattering and hydrophobicity

• Two kinds of PMMA 3D nanostructures fabricated by double-layer replica molding.
• Diluted PMMA solvent employed as the replica molding material with high fidelity.
• Sub-20 nm ordered nanogap network shows high SERS effect.
• Long and shot nanorods composite structure shows good water repellency performance.

Nanogaps or sharp protrusions has been proved useful for surface enhanced Raman scatting (SERS) in single-molecule sensing and a low cost method for fabricating SERS active substrate with these naonstructures is very important for practical applications of SERS in clinical or biological area. In this work, PMMA 3D nanostructures with sub-20 nm ordered nanogap network and sharp tips are fabricated by high-fidelity replica molding. The morphology, water repellency property and Raman enhancement effect of the 3D nanostructures are characterized by SEM, water contact angle and SERS. The results show that the 3D nanostructure of rocket-like array has higher SERS enhancement factor (EF) than the 3D nanostructure of nano-lawn due to the ordered nanogaps, and both of them change the surface wettability of PMMA from hydrophilic to hydrophobic, especially for the 3D structure of nano-lawn.

PMMA 3D nanostructures with sub-20 nm nanogaps and sharp nanotips fabricated by double-layer replica molding. The rocket-like array shows higher SERS enhancement factor than PMMA nano-lawn due to the “hot spot” effect of the nanogaps, while the nano-lawn shows better water repellency performance resulted from the composite structure of long nanorods and shot nanorods.Figure optionsDownload as PowerPoint slide