Polymer design for metal chelation

This project is done in collaboration with Prof. Michael Schulz

Ranging from pollutants to rare elements for energy applications, metal ions are a prime target for extraction. One approach to this problem involves the design of polymers with high binding affinity to a given ion. Modelling can assist the design of such polymers by providing a fundamental understanding of the polymer-ion interaction at multiple time and length scales.

We use density functional theory on reduced polymer models (up to 5 monomers in implicit solvent) to quantify the magnitude and specificity of the interaction (mostly electrostatic in nature) between the polymer and the target metal ion.

 

These data are integrated in the development of parameters for polarizable force fields. We use the AMOEBA model based on permanent electrostatic multipole moments to accurately account for electrostatic effects.

 

With these tools, we can simulate the behavior of polymers in a realistic environment, including multiple polymer chains (>20 monomers) and ions in water.

Polymer design for metal ion extraction. The chain is functionalized with ligands designed to specifically interact with one element. We use energy decomposition analysis of density functional theory to understand the nature of the interaction between the ions and the polymer.

With classical molecular dynamics simulations, we can sample the conformational ensemble of a system of polymers in an ionic environment and compute a binding affinity that includes both enthalpic and entropic contributions.

Schematic representation of a molecular dynamics simulation box for polymer  design, which includes two types of polymers and ions in water (not represented).