Final Report: Understanding Coatings that Protect Plasmonic Structures for Materials Characterization and Detection and Identification of Chemical, Biological and Explosive Agents

We have elucidated the means by which an Al2O3 protective coating prevents chemical and mechanical degradation of a silver plasmonic structure to enable Tip Enhanced Raman Spectroscopy for high resolution, high sensitivity characterization of nanostructures and detection of threats. The protective coating is very effective for measurements in air, preventing chemical degradation of the underlying silver plasmonic structure even after three months of aging. In addition, the protection is partially effective in aqueous environment. Notably, detection of different non-Raman resonant polymer isotopes at the surface was demonstrated for the first time and a new technique developed to independently measure isotopic compositions in the top monomolecular layer of a blend film using mass spectrometry. This technique we call Surface Layer-Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (SL-MALDI-ToF MS). (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: