In a Macromolecules paper, we used molecular dynamics (MD) simulations to probe the behavior of water in two hydrated sulfonated polysulfones with different ion distributions along the polymer backbone. We showed that the melting water in such hydrated polymers consists of water molecules that can hydrogen bond to 4 nearby water molecules, no matter if such water molecules are within the primary hydration shells of some ions and polar groups or not. In other words, for water confined within hydrated polysulfones aggregated water molecules may crystallize but isolated water molecules or few-molecule clusters cannot crystallize.

In a Macromolecules paper, we used molecular dynamics (MD) simulations to probe hydration, fixed ion spacing, and cation-anion interaction in two sulfonated polysulfones with different ion distributions along the polymer backbone. We showed the Manning theory of counterion condensation can be extended to understand the condensation phenomenon of mobile ions  onto the fixed ions on the polymer backbone. We also revealed the formation of fibril-like ionic aggregates in the hydrated sulfonated polysulfones that can percolate the polymer matrix when the water content is below the equilibrium water uptake.