物理化学学报 >> 2016, Vol. 32 >> Issue (7): 1722-1726.doi: 10.3866/PKU.WHXB2016032807

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室温下Kelvin探针力显微镜分析离子液体的界面

张小宁1,*(),胡红美2   

  1. 1 Department of Mathematics, Sciences and Technology, Paine College, Augusta 30901, Georgia, USA
    2 浙江省海洋水产研究所,浙江省海水增养殖重点实验室,浙江舟山316021
  • 收稿日期:2015-12-25 发布日期:2016-07-08
  • 通讯作者: 张小宁 E-mail:XZhang@paine.edu
  • 基金资助:
    美国国家科学基金会(HRD-1505197)

Investigation of Interfaces of Ionic Liquid via Kelvin Probe Force Microscopy at Room Temperature

Xiao-Ning ZHANG1,*(),Hong-Mei HU2   

  1. 1 Department of Mathematics, Sciences and Technology, Paine College, Augusta 30901, Georgia, USA
    2 Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan 316021, Zhejiang Province, P. R. China
  • Received:2015-12-25 Published:2016-07-08
  • Contact: Xiao-Ning ZHANG E-mail:XZhang@paine.edu
  • Supported by:
    the National Science Foundation, USA(HRD-1505197)

摘要:

研究离子液体阳离子和阴离子在界面的排列具有意义,因为它们能够影响离子液体在界面的表面结构和属性。作为一种扫描探针显微技术,Kelvin探针力显微镜(KPFM)在本文中被用于室温下离子液体界面性质的研究。离子液体氯化(1-丁基-3-甲基咪唑)([Bmim]Cl)在本文中被用作研究对象。实验中,[Bmim]Cl被选择性地固定在亲液的化学修饰表面,形成超薄的固态吸附层和液滴。由于表面电势能够用于直接指示表面偶极子,因而对于检测分子的取向十分有用。利用KPFM获得的表面电势图表明[Bmim]Cl离子液体在气液界面(当离子液体以液滴形式存在)和气固界面(当离子液体以固态吸附层形式存在)呈现出不同的分子排列。我们的研究表明Kelvin探针力显微镜能够用于表征离子液体在界面的分子排列。

关键词: Kelvin探针力显微镜, 氯化(1-丁基-3-甲基咪唑), 表面电势, 离子液体的分子排列, 界面

Abstract:

The alignment of the ionic liquid (IL) cation and anion at the interface is of interest because it would affect the surface structures and properties of IL at the interfaces. In this study, Kelvin probe force microscopy (KPFM), a scanning probe microscopy technique, was used to investigate the interfacial properties of the IL at room temperature. A model molecule, 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), was selectively assembled on the lyophilic chemical patterns prepared on a substrate, forming ultrathin solid-like adsorbate layers and droplets. Because the surface potential is a direct indicator of the surface dipole, which is useful for examining molecular orientation, the surface potential maps captured by KPFM indicated that the [Bmim]Cl molecules demonstrated different orientations at the gas-liquid interface (in the form of a droplet) and at the gassolid interface (in the form of a solid-like adsorbate layer). Our results indicate that KPFM has potential for the characterization of IL molecular alignment at interfaces.

Key words: Kelvin probe force microscopy, 1-Butyl-3-methylimidazolium chloride, Surface potential, Ionic liquid molecular arrangement, Interface

MSC2000: 

  • O647