Nakamura Issei, Balsara Nitash P, Wang Zhen-Gang
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Department of Chemical Engineering, University of California, Berkeley, California 94720, United States.
ACS Macro Lett. 2013 Jun 18;2(6):478-481. doi: 10.1021/mz4001404. Epub 2013 May 16.
We study the microphase separation of block copolymer electrolytes containing lithium salts. Taking poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as an example, we show that in the presence of lithium salts the disordered-to-lamellar phase transition becomes first-order even at the level of mean-field theory, with a moderate range of temperature in which both the disordered and lamellar phases coexist, and different salt concentration in the coexisting phases. The coexistence arises from the different partitioning of the salt ions between the disordered phase and the lamellar phase, driven primarily by the solvation energy of anions. A striking consequence of the coexistence is that heating a lamellar phase into the coexistence region leads to increased order in the remaining lamellar phase.
我们研究了含锂盐的嵌段共聚物电解质的微相分离。以聚（环氧乙烷）-b-聚苯乙烯（PEO-b-PS）为例，我们表明，在锂盐存在的情况下，即使在平均场理论水平下，无序到层状的相变也变为一级相变，存在一个适度的温度范围，在此范围内无序相和层状相共存，且共存相中盐浓度不同。这种共存源于盐离子在无序相和层状相之间的不同分配，主要由阴离子的溶剂化能驱动。共存的一个显著结果是，将层状相加热到共存区域会导致剩余层状相的有序度增加。
