Multiscale simulations of block copolymers

COMP 96

Jan Andzelm, jandzelm@arl.army.mil1, Frederick L. Beyer, flbeyer@arl.army.mil2, James F. Snyder, jsnyder@arl.army.mil1, and Peter W Chung3. (1) Materials Division, Multifunctional Materials Branch, U. S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005, (2) Weapons and Materials Research Directorate, U. S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5067, (3) U. S. Army Research Laboratory, AMSRD-CI-HC, Aberdeen Proving Ground, Aberdeen, MD 21005
Block copolymers exhibit unique properties useful in diverse types of applications such as fuel cells, batteries or protective and breathable barriers. We are particularly interested in copolymers with sulfonated polystyrene (sPS) component such as sSIBS or the Li-sPS-POEM copolymer. The sSIBS (sPS-b-polyisobutylene-b-sPS) block copolymer exhibits desirable permeable properties necessary for a breathable barrier while the Li-sPS-POEM (Li-sPS-poly(oxy-ethylene)x methacrylate) might be used as a single-ion conducting electrolyte in lithium-batteries.

In this work, we have used multiscale modeling to gain understanding of static and dynamic properties of these copolymers at detailed atomistic and mesoscale levels. We have used atomistic modeling to develop input parameters for the mesoscale simulations. Using the mesoscale approach, morphology and the microphase ordering mechanisms were calculated. The accuracy of the mesoscale technique is validated in calculations for the experimentally known phase diagram of PS-PI (polystyrene-polyisoprene) copolymer. Mechanical properties based on the mesoscale-calculated morphology were calculated using the self-consistent homogenization theory.