Soft biomimetic tapered nanostructures for large-area antireflective surfaces and SERS sensing

We report a facile fabrication method for the fabrication of functional large area nanostructured polymer films using a drop casting technique. Reusable and tapered silicon molds were utilized in the production of functional polymers providing rapid fabrication of the paraboloid nanostructures at the desired structural heights without the requirement of any complex production conditions, such as high temperature or pressure. The fabricated polymer films demonstrate promising qualities in terms of antireflective, hydrophobic and surface enhanced Raman spectroscopy (SERS) features. We achieved up to 92% transmission from the single-side nanostructured polymer films by implementing optimized nanostructure parameters which were determined using a finite difference time domain (FDTD) method prior to production. Large-area nanostructured films were observed to enhance the Raman signal with an enhancement factor of 4.9 x 10(6) compared to bare film, making them potentially suitable as freestanding SERS substrates. The utilized fabrication method with its demonstrated performances and reliable material properties, paves the way for further possibilities in biological, optical, and electronic applications.