Modeling the Molecular Properties of Polymer Membranes for Water Purification

Michael Shirts, University of Virginia

Usage Details

The diffusion and activity coefficients of water and salts in charged polymer membranes depends very exquisitely on the properties of the polymers themselves. Because the polymers involved in salt separations generally have very large monomer units, and have strong charged interactions forcing the polymers to swell, fairly long chains are required to simulate bulk behavior, and can take a while to equilibrate. The properties of these membranes involved thus involve both relatively large-scale behaviors (out to multiple tens of nanometers) and long time scales (out to at least microseconds) to observe concerted motions involving both polymers and ions. It requires highly parallelized computing of systems such as Blue Waters to be able to address both the length and time scales involved in understanding salt and water transport. The size problems become even more problematic once one actually simulates membrane/solvent interfaces, as the systems must be large enough for the interior of the membrane to have bulk behavior.

Intern Drew Bierdermann will perform many of the computations at shorter scales using local computing resources, but will learn to carry out effective simulations over hundreds and thousands of cores and will be able to determine the most effective way to achieve scientific objectives with different sizes of simulations.