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Microphase Separation Behavior (microphase + separation_behavior)
Selected AbstractsMicrophase separation behavior on the surfaces of poly(dimethylsiloxane)- block -poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) diblock copolymer coatingsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Zheng-Hong Luo Abstract Microphase separation behavior on the surfaces of poly(dimethylsiloxane)- block -poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) (PDMS- b -PHFBMA) diblock copolymer coatings was investigated. The PDMS- b -PHFBMA diblock copolymers were successfully synthesized via atom transfer radical polymerization (ATRP). The chemical structure of the copolymers was characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Surface composition was studied by X-ray photoelectron spectroscopy. Copolymer microstructure was investigated by atomic force microscopy. The microstructure observations show that well-organized phase-separated surfaces consist of hydrophobic domain from PDMS segments and more hydrophobic domain from PHFBMA segments in the copolymers. The increase in the PHFBMA content can strengthen the microphase separation behavior in the PDMS- b -PHFBMA diblock copolymers. And the increase in the annealing temperature can also strengthen the microphase separation behavior in the PDMS- b -PHFBMA diblock copolymers. Moreover, Flory-Huggins thermodynamic theory was preliminarily used to explain the microphase separation behavior in the PDMS- b -PHFBMA diblock copolymers.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Ordering Behavior of Layered Silicate Nanocomposites with a Cylindrical Triblock CopolymerMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2006Chung Ho Lee Abstract Summary: The ordering behavior of the nanocomposites of organically modified montmorillonite (OMMT) with a cylindrical triblock copolymer of polystyrene- block -poly(ethylene- co -butylene)- block -polystyrene (SEBS) has been investigated by temperature-resolved small-angle X-ray scattering (SAXS) and rheometry. X-Ray diffraction (XRD) confirms that the polymer chains are successfully intercalated with the interlayer gallery of the silicates. The data obtained from the SAXS and rheological measurements show that the addition of OMMT leads to a change in the microphase separation behavior of SEBS in the nanocomposites. The molecular interaction between OMMT and the polystyrene (PS) chains of SEBS decreases the structural perfection of the self-assembling, phase-separated domain structure of the nanocomposites. Rheological data exhibit that the order-order (TOOT) and order-disorder transitions (TODT) of the SEBS/OMMT nanocomposites decrease with the addition of OMMT. The highest elongation at break is obtained at approximately 2% OMMT and its further addition to the mixture leads to decreases in tensile strength and elongation. The change in the storage modulus (G,) of a) SEBS, b) S98M2, c) S95M5, and d) S90M10, as a function of temperature in the range of 150,,,T (°C),,,260. [source] | ||||||||||