Shape, size, and structural control of reverse micelles in diglycerol monomyristate nonionic surfactant system.
Shape, size, and structural control of reverse micelles in diglycerol monomyristate nonionic surfactant system.
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DOI：
10.1021/jp067546d
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发表时间：
2007-01
期刊：
影响因子：
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通讯作者：
L. Shrestha;Takaaki Sato;K. Aramaki
中科院分区：
文献类型：
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作者：
L. Shrestha;Takaaki Sato;K. Aramaki
研究了肉豆蔻酸双甘油酯（DGM）在不同类型有机溶剂中的自组织结构。相行为的研究表明，在较低的温度下，固体的存在下，并在温度升高时，固相转化为层状液晶（L（α））相在表面活性剂轴在所有的DGM/油系统。然而，在稀释区域中，观察到固体或L（α）相的分散，这取决于溶剂和温度。在较高温度下，L（α）相熔化成各向同性反胶束溶液相。由互补建模方法支持的小角X射线散射数据的GIFT分析明确表明，DGM反聚集体的结构可以通过优化溶剂油的基本性质来灵活控制。在芳香油中，观察到的适度胶束伸长几乎完全由芳香环的极性决定，烃侧链基团的长度没有显示出剧烈的影响。相反，当用直链烃油代替溶剂时，出现取决于链长的剧烈效果;通过从癸烷到十六烷逐渐增加长度，最终使癸烷中的长圆柱形颗粒转变为平面聚集体，其机理可以根据双甘油部分从亲水环境向具有不同的亲水性的烃油的转移自由能来解释链长我们还系统地研究了温度、表面活性剂浓度和添加水的影响。
We have investigated the self-organization structures of diglycerol monomyristate (DGM) in different types of organic solvents. Study of phase behavior shows the presence of solid at lower temperature, and upon increasing temperature, the solid phase transforms to lamellar liquid crystal (L(alpha)) phase in the surfactant axis in all the DGM/oil systems. In the dilute regions, however, the dispersion of the solid or L(alpha) phase is observed, depending on the solvent and temperature. At higher temperatures, the L(alpha) phase melts to the isotropic reverse micellar solution phase. GIFT analysis of small-angle X-ray scattering data supported by a complementary modeling method have unambiguously shown that the structure of the DGM reverse aggregates can flexibly be controlled by optimizing the fundamental properties of solvent oils. In aromatic oils, the observed moderate micellar elongation is almost solely governed by the polarity of the aromatic ring, the length of the hydrocarbon side chain group showing no drastic effect. In contrast, when the solvent is replaced with linear-chain hydrocarbon oils, the drastic effects depending on the chain length emerge; by gradually increasing the length from decane to hexadecane, the long cylindrical particles in decane are finally transformed into planar aggregates, whose mechanism may be explained in terms of the transfer free energy of the diglycerol moiety from the hydrophilic environment to the hydrocarbon oils with a different chain length. We have also systematically examined the effects of temperature, the surfactant concentration, and added water.