(505c) Multiscale Modelling of Sibs and Sulfonated Sibs Copolymers

An important class of thermoplastic elastomers involves styrenic and polyisobutylene blocks (SIBS). Numerous linear triblock and multi-arm star SIBS copolymers were synthesized and their mechanical and morphology properties were studied. Sulfonated SIBS Triblock Copolymers (S-SIBS) are of particular interest because of potential applications for fuel cell and textile applications, where breathable, protective clothing is required. We have used multiscale modeling to gain an understanding of the static and dynamic properties of these polymer systems at detailed atomistic and mesoscale levels. Quantum chemistry tools were used to elucidate the bonding of water molecules and sulfonate groups. In addition, Molecular Dynamics was applied to calculate the polymer density at various levels of sulfonation and in the presence of Zn, Cu, Ca, Mg and Ba ions. The structure of polymer with ions and also water and alcohol was studied and the channels allowing for diffusion were identified. The diffusion coefficients were calculated and compared to experimental data. Next, the mean-field dynamic density functional theory was utilized to obtain the morphology for a range of triblock and three-arm star SIBS block copolymers at mesoscale levels. Using these results permeability of water was calculated via the finite element method. A comparison between the theoretical results and recent experimental work will be presented.