Alkyl chain interaction at the surface of room temperature ionic liquids: systematic variation of alkyl chain length (R = C(1)-C(4), C(8)) in both cation and anion of [RMIM][R-OSO(3)] by sum frequency generation and surface tension.
Alkyl chain interaction at the surface of room temperature ionic liquids: systematic variation of alkyl chain length (R = C(1)-C(4), C(8)) in both cation and anion of [RMIM][R-OSO(3)] by sum frequency generation and surface tension.
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DOI：
10.1021/jp807924g
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发表时间：
2009-01
期刊：
影响因子：
--
通讯作者：
Cherry S. Santos;S. Baldelli
中科院分区：
文献类型：
--
作者：
Cherry S. Santos;S. Baldelli
用表面和频(SFG)振动光谱和表面张力测量系统地研究了R链长为C(1)-C(4)和C(8)的无卤代1，3-二烷基咪唑烷基硫酸盐[RMIM][R-Oso(3)]的气液界面。从SFG谱中观察到所有离子液体样品的振动模式都来自于正、负离子的甲基。这些结果表明，这两种离子都存在于气液界面，表面张力测量进一步支持了这一点。表面张力数据显示，随着咪唑正离子中的烷基链从甲基链到丁基链的变化，表面张力有下降的趋势，具有特定的阴离子。当阴离子的烷基链被修饰而阳离子被固定时，也观察到类似的趋势。
The gas-liquid interface of halide-free 1,3-dialkylimidazolium alkyl sulfates [RMIM][R-OSO(3)] with R chain length from C(1)-C(4) and C(8) has been studied systematically using the surface-specific sum frequency generation (SFG) vibrational spectroscopy and surface tension measurements. From the SFG spectra, vibrational modes from the methyl group of both cation and anion are observed for all ionic liquid samples considered in the present study. These results suggest the presence of both ions at the gas-liquid interface, which is further supported by surface tension measurements. Surface tension data show a decreasing trend as the alkyl chain in the imidazolium cation is varied from methyl to butyl chain, with a specific anion. A similar trend is observed when the alkyl chain of the anion is modified and the cation is fixed.