PMSE 64 |
| Density changes in a hydrogel covalently bound to the surface of a nanostructured gold film yield large changes in the NIR-visible transmission spectra of the film due to surface plasmon resonance. These hydrogel volume changes are the result of varying electrostatic repulsion between acrylic acid groups incorporated into the gel and depend upon the pH of the surrounding aqueous solution. In the presence of basic solutions, the charged state of the hydrogel causes swelling, while acidic media results in a protonated and uncharged gel that collapses. When spherical gold nanoparticles (Au NPs) of varying sizes are incorporated into the hydrogel, a larger spectroscopic response is seen during these gel density changes. This spectroscopic enhancement results from changes in the Au NP-Au NP and Au NP-nanostructured gold surface plasmon resonance coupling, which are a function of their respective relative distances from each other. The swelling of the hydrogel causes the Au NPs, on average, to be pulled farther away from each other as well as from the nanostructured gold surface. We have utilized this enhancement to optically measure the carboxylate-cation coordination in the gel when the counterions in the basic media are varied. |
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Synthesis and Self-Assembly Approaches to Polymer-Inorganic Hybrid Nanoparticles
8:30 AM-12:00 PM, Monday, April 7, 2008 Hilton New Orleans Riverside -- Grand Salon 24, Oral
Division of Polymeric Materials: Science & Engineering |