Collaborative Research: Computations, Modeling And Experiments Of Self And Directed Assembly For Nanoscale Liquid Metal Systems

The goal of the proposed research is to investigate the behavior of nanoscale liquid metal drops on surfaces with a comprehensive approach of simulations, modeling and experiments. Placing such nanodrops on different surfaces in a controlled way is important for manufacturing surfaces with unique material properties that can be used in microelectronic devices, in solar panels, in spectroscopy and even in radiation treatment for cancer.The proposed work explores competing capillary, viscous and inertial forces in the collapse versus breakup of nanoscale liquid metal filaments, liquid metal-substrate interactions, and thermal effects where nanoscale thermal gradients will be imposed via templating and temperature dependent material properties. The traNational Science Foundation ormative aspect of this proposal resides in providing new insights into the emerging field of complex and multi-component nanoparticle synthesis with enhanced functionality. Research efforts put forward in this proposed work focus on developing direct numerical methods for solving fully 3D Navier-Stokes equations in combination with targeted experiments. Specifically, accurate numerical methods will be developed based on the multi-material Volume of Fluid approach, also incorporating triple junctions and moving contact lines, as well as the potentials describing liquid-solid interactions. To challenge the computations, the physical experiments are designed to interrogate various metal/alloy-substrate combinations which will probe the relevant hydrodynamic and chemical instabilities. A distinguishing feature of the proposed project is the immediate and direct comparison of numerical results with the experimental ones. The theoretical, computational, and experimental work will drive each other, with theoretical predictions directly checked by experiments, and subsequently these experiments will be used to develop more accurate theoretical description of the instabilities and transport of nanoscale liquid metals. The results of this research will be of interest to a wide community exploring experimental and computational fluid dynamics and more generally to the researchers considering various aspects of nanoscience. The broader impact of the proposed work resides in providing new insights into the emerging field of complex and multi-component nanoparticle synthesis with enhanced functionality. The proposed work is expected to have an impact on a number of applications. Examples include metal-particle based plasmonic structures for enhanced solar cells and waveguides, where it is of interest to have a substrate covered by ordered arrays of metallic nanoparticles. The proposal also includes the development of software that will be available to researchers in the community, and educational activities for graduate and undergraduate students.