Hall and Sampath's article featured on cover of Journal of Chemical Physics

A paper from Lisa Hall and researcher Janani Sampath entitled "Impact of Ionic Aggregate Structure on Ionomer Mechanical Properties from Coarse-Grained Molecular Dynamics Simulations"  has been featured on the cover of the Journal of Chemical Physics (Volume 147, Issue 13), published by the American Institute of Physics (API).

Using coarse-grained molecular dynamics simulations, Hall and Sampath studied ionomers in equilibrium and under uniaxial tensile deformation. The spacing of ions along the chain was varied, allowing the researchers to consider how different ionic aggregate morphologies, from percolated to discrete aggregates, impacted the mechanical properties. From the equilibrium simulations, they calculated the stress-stress auto correlation function, showing a distinct deviation from the Rouse relaxation due to ionic associations that depends on ion content. They then quantified the morphology during strain, particularly the degree to which both chains and ionic aggregates tend to align. They also tracked the location of the ionomer peak in the anisotropic structure factor during strain. The length scale of aggregate order increased in the axial direction and decreased in the transverse direction, in qualitative agreement with prior experimental results.

The article may be viewed in its entirety at https://doi.org/10.1063/1.4985904