TY - JOUR
T1 - Phase Behavior of Mixtures of Block Copolymers and a Lithium Salt
AU - Loo, Whitney S.
AU - Galluzzo, Michael D.
AU - Li, Xiuhong
AU - Maslyn, Jacqueline A.
AU - Oh, Hee Jeung
AU - Mongcopa, Katrina I.
AU - Zhu, Chenhui
AU - Wang, Andrew A.
AU - Wang, Xin
AU - Garetz, Bruce A.
AU - Balsara, Nitash P.
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/8/23
Y1 - 2018/8/23
N2 - We present experimental results on the phase behavior of block copolymer/salt mixtures over a wide range of copolymer compositions, molecular weights, and salt concentrations. The experimental system comprises polystyrene-block-poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. It is well established that LiTFSI interacts favorably with poly(ethylene oxide) relative to polystyrene. The relationship between chain length and copolymer composition at fixed temperature is U-shaped, as seen in experiments on conventional block copolymers and as anticipated from the standard self-consistent field theory (SCFT) of block copolymer melts. The phase behavior can be explained in terms of an effective Flory-Huggins interaction parameter between the polystyrene monomers and poly(ethylene oxide) monomers complexed with the salt, χeff, which increases linearly with salt concentration. The phase behavior of salt-containing block copolymers, plotted on a segregation strength versus copolymer composition plot, is similar to that of conventional (uncharged) block copolymer melts, when the parameter χeff replaces χ in segregation strength.
AB - We present experimental results on the phase behavior of block copolymer/salt mixtures over a wide range of copolymer compositions, molecular weights, and salt concentrations. The experimental system comprises polystyrene-block-poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. It is well established that LiTFSI interacts favorably with poly(ethylene oxide) relative to polystyrene. The relationship between chain length and copolymer composition at fixed temperature is U-shaped, as seen in experiments on conventional block copolymers and as anticipated from the standard self-consistent field theory (SCFT) of block copolymer melts. The phase behavior can be explained in terms of an effective Flory-Huggins interaction parameter between the polystyrene monomers and poly(ethylene oxide) monomers complexed with the salt, χeff, which increases linearly with salt concentration. The phase behavior of salt-containing block copolymers, plotted on a segregation strength versus copolymer composition plot, is similar to that of conventional (uncharged) block copolymer melts, when the parameter χeff replaces χ in segregation strength.
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U2 - 10.1021/acs.jpcb.8b04189
DO - 10.1021/acs.jpcb.8b04189
M3 - Article
C2 - 30067357
AN - SCOPUS:85052335608
SN - 1520-6106
VL - 122
SP - 8065
EP - 8074
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 33
ER -