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Effect Of Chain Architecture And Surface Energies On The Ordering Behavior Of Lamellar And Cylinder Forming Block Copolymers, V. Khanna, Eric W. Cochran, A. Hexemer, G. E. Stein, G. H. Fredrickson, E. J. Kramer, X. Li, J. Wang, S. F. Hahn
Effect Of Chain Architecture And Surface Energies On The Ordering Behavior Of Lamellar And Cylinder Forming Block Copolymers, V. Khanna, Eric W. Cochran, A. Hexemer, G. E. Stein, G. H. Fredrickson, E. J. Kramer, X. Li, J. Wang, S. F. Hahn
Eric W. Cochran
We investigate the effect of surface energy and chain architecture on the orientation of microdomains in relatively thick films (600-800 nm) of lamellar and cylindrical block copolymers of poly(cyclohexylethylene) (C) and poly(ethylene) (E). The E block has 26 ethyl branches per 1000 backbone carbon atoms. Melt surface energies of the C and E blocks are 22.3 and 20.9 mJ/m 2, respectively. Grazing-incidence small-angle X-ray scattering (GISAXS), scanning force microscopy (SFM), and cross-sectional transmission electron microscopy (TEM) show that cylindrical and lamellar CEC triblock copolymers orient their microdomains normal to the surface throughout the film thickness. However, a lamellar CE diblock …
Semicrystalline Thermoplastic Elastomeric Polyolefins: Advances Through Catalyst Development And Macromolecular Design, Atsushi Hotta, Eric W. Cochran, Janne Ruokolainen, Vikram Khann, Glenn H. Fredrickson, Edward J. Kramer, Yong-Woo Shin, Fumihiko Shimizu, Anna E. Cherian, Phillip D. Hustad, Jeffrey M. Rose, Geoffrey W. Coates
Semicrystalline Thermoplastic Elastomeric Polyolefins: Advances Through Catalyst Development And Macromolecular Design, Atsushi Hotta, Eric W. Cochran, Janne Ruokolainen, Vikram Khann, Glenn H. Fredrickson, Edward J. Kramer, Yong-Woo Shin, Fumihiko Shimizu, Anna E. Cherian, Phillip D. Hustad, Jeffrey M. Rose, Geoffrey W. Coates
Eric W. Cochran
We report the design, synthesis, morphology, phase behavior, and mechanical properties of semicrystalline, polyolefin-based block copolymers. By using living, stereoselective insertion polymerization catalysts, syndiotactic polypropylene-block-poly(ethylene-co-propylene)-block-syndiotactic polypropylene and isotactic poly propylene-block-regioirregular poly propylene-block- isotactic polypropylene triblock copolymers were synthesized. The volume fraction and composition of the blocks, as well as the overall size of the macromolecules, were controlled by sequential synthesis of each block of the polymers. These triblock copolymers, with semicrystalline end-blocks and mid-segments with low glass-transition temperatures, show significant potential as thermoplastic elastomers. They have low Young's moduli, large strains at break, and better than 90% elastic recovery at …