This Award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The morphology and size dependence of the Hamaker constants for gold and silver nanoparticles will be investigated theoretically and experimentally using time resolved optical absorption spectroscopy applied to the precipitation dynamics of the nanoparticles. The goal of this project is to show experimentally and theoretically that the Hamaker constant is size and morphology dependent for noble metal nanoparticles. Absorption spectroscopy will be used to monitor the dynamics of the precipitation of noble nanoparticles as a function of the salt concentration of the solution containing them. The kinetics of precipitation will be used to calculate the Hamaker constant of the nanoparticles of different size and morphology. The main hypothesis of the project is that the Hamaker constant for small noble nanoparticles is size and morphology dependent and this is the reason for the deviations in the reported literature values of these constants for noble metals. The size dependence of the Hamaker constant stems from the size effect for the Surface Plasmon Resonance in noble metal nanoparticles, which might contribute significantly to the Hamaker constant. The results of this project will establish a fundamental relation between fluctuation-dissipation forces and collective electronic excitations known as Surface Plasmon Resonances in metal nanoparticles and will facilitate our capability to simulate interaction on the nanoscale and to model the self-assembly of metal nanoparticles.
NON-TECHNICAL SUMMARY:
Metal nanoparticles are the major components of the bottom-up self-assembly fabrication process and play an increasingly important role in the development of biochemical sensors, optical subwavelength waveguides and nano-optics. Understanding the forces between metal nanoparticles is a precondition for the fine and precise control of the self-assembly process. This project will investigate the forces acting between nanoparticles in solution and lead to better control over the self assembly process. The results of this study will have a profound effect on the development of nanotechnology in the area of self-assembly of nanoparticles and will have a significant educational influence. Understanding the interaction potential between metal nanoparticles is essential for the development of new and efficient nanofabrication technologies. The rapid development of nanotechnology and nanofabrication requires adequate training of undergraduate and graduate students in order to keep up with the new trends and to match the growing needs of these expanding sectors of research and economy. Undergraduate and graduate students need to meet the challenges of this expansion with sufficient background and training. This project will combine research and education programs to properly prepare graduate and undergraduate students for this kind of research in nanotechnology.
