Morphologies of ABC Triblock Terpolymer Melts Containing Poly(Cyclohexadiene): Effects of Conformational Asymmetry

Journal Article · Sun Dec 23 00:00:00 EST 2012 · Langmuir

DOI:https://doi.org/10.1021/la304576c· OSTI ID:1060860

Kumar, Rajeev ^[1]; Sides, Scott W. ^[2]; Goswami, Monojoy ^[3]; Sumpter, Bobby G. ^[4]; Hong, Kunlun ^[4]; Wu, Xiaodong ^[5]; Russell, Thomas P. ^[5]; Gido, Samuel P. ^[5]; Misichronis, Konstantinos ^[6]; Rangou, Sofia ^[6]; Avgeropoulos, Apostolos ^[6]; Tsoukatos, Thodoris ^[7]; Hadjichristidis, Nikos ^[7]; Beyer, Frederick L. ^[8]; Mays, Jimmy W. ^[9]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Sciences
2. Tech-X Corporation, Boulder, CO (United States)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Sciences and Mathematics Division
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
5. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Polymer Science and Engineering
6. Univ. of Ioannina (Greece). Dept. of Materials Science & Engineering
7. Univ. of Athens (Greece). Dept. of Chemistry
8. US Army Research Lab., Aberdeen Proving Ground, MD (United States)
9. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

We have synthesized linear ABC triblock terpolymers containing poly(1,3-cyclohexadiene), PCHD, as an end block and characterized their morphologies in the melt. Specifically, we have studied terpolymers containing polystyrene (PS), polybutadiene (PB), and polyisoprene (PI) as the other blocks. Systematically varying the ratio of 1,2- /1,4-microstructures of poly(1,3-cyclohexadiene), we have studied the effects of conformational asymmetry among the three blocks on the morphologies using transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and self-consistent field theory (SCFT) performed with PolySwift++. Our work reveals that the triblock terpolymer melts containing a high percentage of 1,2-microstructures in the PCHD block are disordered at 110 °C for all the samples, independent of sequence and volume fraction of the blocks. In contrast, the triblock terpolymer melts containing a high percentage of 1,4-microstructure form regular morphologies known from the literature. The accuracy of the SCFT calculations depends on calculating the χ parameters that quantify the repulsive interactions between different monomers. Simulations using χ values obtained from solubility parameters and group contribution methods are unable to reproduce the morphologies as seen in the experiments. However, SCFT calculations accounting for the enhancement of the χ parameter with an increase in the conformational asymmetry lead to an excellent agreement between theory and experiments. Lastly, these results highlight the importance of conformational asymmetry in tuning the χ parameter and, in turn, morphologies in block copolymers.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1060860
• Journal Information: Langmuir, Vol. 29, Issue 6; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE