Ionic liquids as modulators of physicochemical properties and nanostructures of sodium dodecyl sulfate in aqueous solutions and potential application in pesticide microemulsions
Ionic liquids as modulators of physicochemical properties and nanostructures of sodium dodecyl sulfate in aqueous solutions and potential application in pesticide microemulsions
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离子液体作为十二烷基硫酸钠水溶液理化性质和纳米结构的调节剂及其在农药微乳液中的潜在应用
DOI：
10.1039/c6cp04722j
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发表时间：
2016-11-21
影响因子：
3.3
通讯作者：
Wu, Xuemin
中科院分区：
文献类型：
--
作者：
Li, Jing;Fan, Tengfei;Wu, Xuemin
农药微乳剂乳化剂中含有部分挥发性有机化合物，离子液体正成为其潜在的替代品。为了将离子液体应用于农药微乳剂中，有必要研究离子液体与表面活性剂的相互作用。因此，本文研究了阴离子表面活性剂十二烷基硫酸钠（SDS）在离子液体中的表面性质和聚集行为，包括N-己基-N-甲基吗啉基溴（[C（6）mm][Br]）、N-己基-N-甲基哌啶基溴（[C（6）mp][Br]）、N-己基-N-甲基吡咯烷基溴（[C（6）mpyr][Br]）、N-辛基-N-甲基吡咯烷基溴（[C（8）mpyr][Br]）、研究了N-十二烷基-N-甲基吡咯烷基溴（[C（12）mpyr][Br]）和N-十六烷基-N-甲基吡咯烷基溴（[C（16）mpyr][Br]）的表面张力、电导率、动态光散射（DLS）、粘度、荧光、伪三元相图和H-1 NMR。一般来说，这些方法提供了各种胶束参数的评估，如临界胶束浓度（CMC），反离子化程度（α），最大表面过量浓度（Gamma（max））、每个表面活性剂头基的最小面积（A（min））以及一些热力学参数，包括胶束化的标准自由能（Δ S-m（0））、标准胶束化焓（Δ H-m（0））和标准胶束化熵（Δ S-m（0））。结果表明，疏水效应作为自发的，放热的，熵驱动的胶束化过程的主要力量。利用1H-1 NMR技术研究了离子液体在SDS胶束水溶液中的增溶位置和相互作用。荧光，DLS和粘度测量显示相当大的胶束形态和各种相行为。此外，还成功制备了10%苯醚甲环唑微乳剂，并在混剂中表现出良好的稳定性和铺展性，表明离子液体在农药制剂中具有潜在的应用价值。
Emulsifiers for pesticide microemulsions contain a part of volatile organic compounds (VOCs), and ionic liquids (ILs) are becoming potential substitutes. In order to apply ILs in pesticide microemulsions, the study of interaction between ILs and surfactants is necessary. Therefore, the surface properties and aggregation of anionic surfactant sodium dodecyl sulfate (SDS) in ILs, including N-hexyl-N-methylmorpholinyl bromide ([C(6)mm][Br]), N-hexyl-N-methylpiperidyl bromide ([C(6)mp][Br]), N-hexyl-N-methylpyrrolidyl bromide ([C(6)mpyr][Br]), N-octyl-N-methylpyrrolidyl bromide ([C(8)mpyr][Br]), N-dodecyl-N-methylpyrrolidyl bromide ([C(12)mpyr][Br]) and N-hexadecyl-N-methylpyrrolidyl bromide ([C(16)mpyr][Br]), were investigated in terms of surface tension, conductivity, dynamic light scattering (DLS), viscosity, fluorescence, pseudo-ternary phase diagram and H-1 NMR measurements. Generally in agreement, the methods afforded the evaluation of various micellar parameters such as critical micelle concentration (CMC), degree of counterion ionization (alpha), the maximum surface excess concentration (Gamma(max)), the minimum area per surfactant headgroup (A(min)) as well as some thermodynamic parameters, including standard free energy of micellization (Delta S-m(0)), standard enthalpy of micellization (Delta H-m(0)) and standard entropy of micellization (Delta S-m(0)). The results indicated a hydrophobic effect as the primary force of a spontaneous, exothermic, entropy driven micellization process. H-1 NMR technique was applied to reveal the solubilization site and interaction of ILs in aqueous SDS micellar solutions. Fluorescence, DLS and viscosity measurements revealed considerable micellar morphologies and various phase behaviors. Furthermore, the 10% difenoconazole microemulsion was successfully prepared and showed good stability and spreadability in mixtures which indicated ILs' potential application in pesticide formulation.