Ordering transition in salt-doped diblock cpolymers.
Lithium salt-doped block copolymers offer promise for applications as solid electrolytes in lithium ion batteries. Control of the conductivity and mechanical properties of these materials, for membrane applications relies critically on the ability to predict and manipulate their microphase separation temperature. Past attempts to predict the so-called "order-disorder transition temperature" of copolymer electrolytes have relied on approximate treatments of electrostatic interactions. In this work, we introduce a coarse-grained simulation model that treats Coulomb interactions explicitly, and we use it to investigate the ordering transition of charged block copolymers. The order-disorder transition temperature is determined from the ordering free energy, which we calculate with a high level of precision using a density-of-states approach. Our calculations allow us to discern a delicate competition between two physical effects: ion association, which raises the transition temperature, and solvent dilution, which lowers the transition temperature. In the intermediate salt concentration regime, our results predict that the order-disorder transition temperature increases with salt content, in agreement with available experimental data.
- Publication Date:
- OSTI Identifier:
- DOE Contract Number:
- Resource Type:
- Journal Article
- Resource Relation:
- Journal Name: Macromolecules; Journal Volume: 49; Journal Issue: 9
- Research Org:
- Argonne National Laboratory (ANL)
- Sponsoring Org:
- USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
- Country of Publication:
- United States