Simultaneous Conduction of Electronic Charge and Lithium Ions in Block Copolymers
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- 作者：Shrayesh N. Patel ; Anna E. Javier ; Greg M. Stone ; Scott A. Mullin ; Nitash P. Balsara
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：February 28, 2012
- 年：2012
- 卷：6
- 期：2
- 页码：1589-1600
- 全文大小：677K
- 年卷期：v.6,no.2(February 28, 2012)
- ISSN：1936-086X
文摘
The main objective of this work is to study charge transport in mixtures of poly(3-hexylthiophene)-b-poly(ethylene oxide) (P3HT鈥揚EO) block copolymers and lithium bis(trifluoromethanesulfonyl) imide salt (LiTFSI). The P3HT-rich microphase conducts electronic charge, while the PEO-rich microphase conducts ionic charge. The nearly symmetric P3HT鈥揚EO copolymer used in this study self-assembles into a lamellar phase. In contrast, the morphologies of asymmetric copolymers with P3HT as the major component are dominated by nanofibrils. A combination of ac and dc impedance measurements was used to determine the electronic and ionic conductivities of our samples. The ionic conductivities of P3HT鈥揚EO/LiTFSI mixtures are lower than those of mixtures of PEO homopolymer and LiTFSI, in agreement with published data obtained from other block copolymer/salt mixtures. In contrast, the electronic conductivities of the asymmetric P3HT鈥揚EO copolymers are significantly higher than those of the P3HT homopolymer. This is unexpected because of the presence of the nonelectronically conducting PEO microphase. This implies that the intrinsic electronic conductivity of the P3HT microphase in P3HT鈥揚EO copolymers is significantly higher than that of P3HT homopolymers.