Phase behavior of SEBS triblock copolymer gels

Dynamic density functional theory calculations were performed for thermoplastic elastomer gels composed of an ABA triblock copolymer immersed in a B‐attractive solvent. The triblock copolymer model was parameterized for polystyrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS), while the solvent model was parameterized for the hydrocarbon oil tetradecane. The effect of the solvent concentration and S‐EB interaction on the morphology was investigated, where complementary experimental data was used to validate results at χ_ABN ≈ 100. Agreement was observed at solvent volume fractions of 0.2, 0.4, and 0.6, which correspond to the cylindrical, spherical, and spherical phases, respectively. Qualitative agreement was observed for 0.8 volume fraction solvent, where a core‐shell spherical micelle morphology was found. For a 50/50 vol % mixture of polymer/solvent, the effect of solvent molecular weight on the morphology was considered, where a transition between micro and macrophase separation was predicted at a critical solvent molecular weight. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1479–1491, 2011