标题：Effect of L64 on the Phase Behavior of 1-Dodecyl-3-methylimidazolium Chloride/Water System
作者：Wang Luyan; Wu Zhiyan; Pei Meishan; Wu Xinzhou; Tao Xutang
作者机构：[Wang, L] School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong 250022, China, State Key Laboratory of Crystal Materials, 更多
通讯作者地址：[Pei, MS]Univ Jinan, Sch Chem & Chem Engn, Jinan 250022, Shandong, Peoples R China.
关键词：[C12mim]Cl;liquid crystal;phase;small-angle X-ray scattering;Fourier transform infrared
摘要：Phase behavior of ternary system involving surfactant-like ionic liquid 1-dodecyl-3-methylimidazolium chloride ([C12mim]Cl), water, and nonionic surfactant PEO-PPO-PEO block copolymer (Pluronic L64) is investigated at 25℃. Hexagonal (H1) and lamellar liquid crystal phase (Lα) are found in [C12mim]Cl/H2O/L64 system by using polarized optical microscopy (POM), small-angle X-ray scattering (SAXS) techniques and 2H NMR spectra. The phase structure (H1 phase), which is formed in [C12mim]Cl/H2O binary system, is not changed when L64 with a low concentration is added. However, phase transitions will occur from hexagonal to multiphases of H1 and cubicphases (C), then to Lα+C phases with constant [C12mim]Cl/H2O ratio and increasing L64 concentration. Moreover,at given L64 (5%, 20%) concentration, the lattice parameter of H1 or Lα phase decreases with increasing [C12mim]Cl/H2O ratio. Fourier transform infrared (FTIR) spectra indicate that the H-bonded network comprising an imidazolium ring, chloride ion and water formed in [C12mim]Cl/H2O binary system is disrupted upon addition of L64. This is helpful to the phase transition, due to the decreasing of interfacial curvature induced by dehydration of hydrated layer after the addition of PEO block of L64.