The aggregation behavior of the triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (L64, PE013PP03oPEO,3) in the room-temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim] [BFJ) was investigated using polarized optical microscopy (POM), small-angle X-ray scattering (SAXS), and Fourier transform infrared (FTIR) spectroscopy. The phase diagram of the L64/[Bmim] [BF4] system is described, where the micellar phase (L1), a mixture of lamellar liquid crystalline (Lo) and L, phases, theLo phase, a mixture of Lo and reverse micellar (L2) phases, and the Lo phase are sequentially mapped. Among these phases, the behavior of the Lo phase formed in the L64/[Bmim][BF4] system in the L64 concentration region of 40%-65% (w, mass fraction) was focused on because it forms highly-ordered structures. The Maltese cross texture was found through POM characterization, and was typical for the Lo phase. The SAXS patterns further confirm the formation of the Lo phase. In addition, the lattice spacings of the Lo phase were obtained from the SAXS patterns. The effect of temperature on the microstructure of the Lo phase was also elucidated. As the temperature was increased, the lattice spacing and ordering of the Lo phase increased, while the interfacial area decreased for a certain temperature range. However, the birefringence of the Lo phase disappeared when the temperature reached a certain level, which was attributed to the breakdown of hydrogen bonding between [Bmim] [BF4] and polyethylene oxide) chains, so the ordering of the Lo phase was decreased. The formation mechanism of the Lo phase is also discussed. Hydrogen bonding, electrostatic and solvophobic interactions are believed to be the main driving forces for the formation of Lo phase in the L64/[Bmim][BF4] system.%利用偏光显微镜(POM)、小角X射线散射(SAXS)及傅里叶变换红外(FTIR)光谱技术研究了嵌段共聚物Pluronic L64 (PEO13PPO30PEO13)(PEO∶聚氧乙烯；PPO:聚氧丙烯)在室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐[Bmim][BF4]中的聚集行为.绘制了L64/[Bmim][BF4]体系的相图,当L64浓度介于40％-65％ (W,质量分数)之间时,L64可与[Bmim][BF4]形成层状液晶.SAXS结果表明,液晶层间距随L64浓度的增加而降低.温度对液晶微结构影响较大,液晶层间距随温度的升高而增大,极性头截面积则减小.并且,在一定温度范围内,升温可使体系的有序性增强.但是,随温度的进一步升高,[Bmim][BF4]与PEO链段之间的氢键被破坏,双折射现象消失,液晶有序性降低.此外,分析了层状液晶的形成机理,[Bmim][BF4]与L64分子间的氢键作用力、静电作用力以及疏溶剂力是液晶形成的驱动力.
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