title: Nonaqueous lyotropic liquid-crystalline phases formed by gemini surfactants in a protic ionic liquid.
abstract: The aggregation behaviors of three Gemini surfactants [(C(s)H(2s)-α,ω-(Me(2)N(+)C(m)H(2m+1)Br(-))(2), s = 2, m = 10, 12, 14] in a protic ionic liquid, ethylammonium nitrate (EAN), have been investigated. The polarized optical microscopy and small-angle X-ray scattering (SAXS) measurements are used to explore the lyotropic liquid crystal (LLC) formation. Compared to the LLCs formed in aqueous environment, the normal hexagonal and lamellar phases disappear. However, with increasing the surfactant concentration, a new reverse hexagonal phase (H(II)) can be mapped over a large temperature range except for other ordered aggregates including the isotropic solution phase and a two-phase coexistence region. The structural parameters of the H(II) are calculated from the corresponding SAXS patterns, showing the influence of surfactant amount, alkyl chain length, and temperature. Meanwhile, the rheological profiles indicate a typical Maxwell behavior of the LLC phases formed in EAN.
authors.affiliation: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Wang
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Yurong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xiu
authors.initials: X
authors.lastname: Yue
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Li
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Li
mesh_terms: D052578:Ionic Liquids / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D010316:Particle Size; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C421484:ethylammonium