It is well known that if the size of any material is reduced to the nanometer scale, its properties change. Many materials, e.g. metallic and polymeric, can now be developed so as to yield new properties when combined on the nanoscale. This project examines the different and useful new properties that can be obtained from a combination of precious metals (silver and gold) and polymers, both having sizes on the nanoscale. The goal of this research is thus to produce, study, and exploit the unique properties of two-dimensional assemblies of nanoparticles having different shapes included within specially-chosen polymers that serve to both stabilize and assemble these nanoparticles. This information will be used to develop more complex structures, such as arrays of two different types of metal nanoparticles and three-dimensional polymer/nanoparticle assemblies, as part of future research plans. The new combination of materials will be examined for potential applications such as optical components, opto-electronic switches and opto-mechanical devices for nanoscale force measurements. These applications could lead to new products, helping technological and economic growth.
PART II: TECHNICAL SUMMARY
The plasmonic properties of silver and gold on the nanoscale have attracted the attention of many researchers in different fields for different exciting applications. The goal of this research is to produce, study, and exploit the unique properties of two-dimensional assemblies of colloidal plasmonic nanoparticles consisting of different shapes with specially-chosen polymers that serve as both stabilizing nanoparticle-capping ligands and assembling agents. The polymers will be used to direct self-assembly of the nanoparticles into highly-ordered plasmonic arrays using the rapid and cost-effective Langmuir-Blodgett monolayer deposition. The ordering of the arrays and the resulting changes in electronic and optical properties through coupling of plasmonic modes on different nanoparticles will be examined using macromolecules of different lengths, chemical functionalities, and compositions. Experiments will be complemented by calculations using the discrete dipole approximation to further fundamentally understand the optical properties of the arrays and how they differ from those of smaller aggregates or individual plasmonic nanoparticles. The arrays will also be examined for their potential use as flexible optical polarizers and filters, opto-electronic switches, and opto-mechanical devices for nanoscale force measurements.
