We have been using atomic and mesoscale modeling methods to explore the properties, functionality and engineering of a variety of nanostructures. This talk will focus on several recent applications. The first is the use of a rod-coil transition in "bottle brush" molecules that are grafted to the inside of a nanopore to control pore size in response to environmental conditions such as temperature and solvent quality. Our simulations demonstrate, for example, that systems of this type can be used to size select molecules as they flow through the functionalized nanopores. A second example is hydrocarbon decomposition on nickel under ultra-fast tip-surface sliding conditions, where simulations are being used to delineate the influence of mechanical bond stretching (e.g. mechano-chemistry) from thermo-chemistry. The implications of these modeling studies on the design of robust nanomachines with moving interfaces will be discussed. A third example is the properties of polarized nanotubes, where a new self-consistent tight-binding scheme is used to characterize electrostatic interactions in nanotube-polymer composites, nanotube alignment and field emission in applied electric fields, and non-equilibrium electron transport in electronic devices and sensors.
The Office of Naval Research, the Department of Energy, and NASA-Ames supported this work.