Chemical functional polymers for direct UV assisted nanoimprinting of polymeric photonic microring resonators

We report the nanoimprinting of a microring resonator (MRR) and the development of a functional nanoimprint polymer as route toward selective MRR biosensors. A hybrid, residual layer-free, UV assisted nanoimprint technique was used to pattern freestanding polymer waveguides with a resolution of 300nm and an aspect ratio of 4:1. A low viscous, functional UV nanoimprint polymer was formulated with a hydroxyl functional acrylate monomer (4-hydroxyl butyl acrylate, HBA). The functional polymer was characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The added hydroxyl groups were found on the polymer surface and were accessible for selective binding of a fluorine tag (trifluoroacetic anhydride, TFAA). The density of the hydroxyl groups was tuned by the HBA concentration. A maximum hydroxyl group density of 8.4% was reached for 33.75wt% HBA. The RMS surface roughness was 1.2-2.2nm. Polymeric photonic MRR with superficial chemical functio nalities for a subsequent biomolecule binding and application as a biosensor.