Hydrogel Nanostructures for Plaxmonic and Biosensor Applications

Plasmonics is recently emerged nanophotonics Research area that focuses at sub-wavelength confinement of light energy by ist coupling to surface Plasmons - collective oscillations in Charge density and associated electromagnetic field at surfaces of metals. Hybrid responsive polymer-metallic nanostructures represent an attractive class of materials with actively tunabel plasmonic properties. Such characteristics ma enable new appications of plasmonics in analytics that utilize direct or optical spectroscopy-based detection of molecular analytes as well as in development of novel miniaturized plasmonic components. This Thesis describes novel implementations of thermo-responsive N-isopropylacrylamide (pNIPAAm) - bases hydrogel to metallic nanostructures that Support suface Plasmons. It reports means of structuring a photo-crosslinkable pNIPPAAm layer with Features exhibiting size as small as 100 nm by nano-imprint lithography and laser interference lithography. A new technique for in situ Observation of swelling characteristics of such nanoscopic soft matter objects that are arranged in a period Array was developed based on optical waveguide mode-enhanced diffractions measurements. pNIPPAAm periodic structures highly swell in water (swelling Ration up to 10( and they can be prepared on around 1 cm2 area on a Gold surface. A structure that acts as a tunable plasmonic Crystal was prepared and by ist reversible swelling and collapsing a plasmonic bandgap can be open and closed. In Addition, responsive pNIPPAAm material was employed as a "glue" in plasmonic structures. Firstly, it was employed to serve as a responsive cushion that tethers a thin metallic film with Arrays of nanoholes to a solid glass surface. The swelling and collapsing of the cushion is demonstrated to mediate the extraordinary Transmission and potentially offer a new means of the implementation of nanohole Arrays surface Plasmon resonance biosensor with flow-troufh architecture. Lastly, pNNIPAAm was used as a glue in order to form a Composite film with high density of nanoparticles that were imprinted with a low molecular weight organic molecule. The Composite film exhibited highly open architecture troufh wich the target analyte L-Boc-phenylalanine-anilide (L-BFA) can freely diffuse and become affinity capture. Derect detection of affinity binding at concentrations around µ was carried by optical waveguide spectroscopy as the Composite film can serve at the same time as large capacity affinity binding Matrix and an optical waveguide.