Viradiya Ravi A, Patel Niraj, Aswal Vinod K, Patel Vaibhav K, Panjabi Sanjay H
Department of Chemical Sciences, P. D. Patel Institute of Applied Sciences, CHARUSAT University, Changa 388421, Gujarat, India.
Organic Chemistry Department, Institute of Science and Technology for Advanced Research (ISTAR), The CVM University, Vallabh Vidyanagar, Anand 388120, Gujarat, India.
Langmuir. 2023 Aug 22;39(33):11684-11693. doi: 10.1021/acs.langmuir.3c01257. Epub 2023 Aug 7.
Two morpholinium-based surface-active ionic liquids (SAILs) with aromatic counterions were synthesized, namely, -dodecyl--methylmorpholinium salicylate [Cmmor][Sal] and -dodecyl--methylmorpholinium 3-hydroxy-2-naphthoate [Cmmor][3--2-], and explored their aggregation behavior in aqueous solutions systematically. Electrical conductivity, small-angle neutron scattering (SANS), surface tension (ST), and UV-vis spectroscopy measurements were employed to determine various thermodynamic, micellar, and interfacial parameters, like the degree of counterion binding (β), critical micelle concentration (CMC), minimum area per molecule (), surface excess concentration (Γ), standard Gibbs free energy of adsorption (Δ), aggregation number (), standard Gibbs free energy of micellization (Δ), standard enthalpy of micelle formation (Δ), and the standard entropy of micellization (Δ) in an aqueous solution. Incorporating the aromatic counterions favors significantly excellent micellization properties over conventional halogenated SAILs such as [Cmmor][Br]. SANS analysis revealed that upon changing the counterion from salicylate to 3-hydroxy-2-naphthoate, the structure changed from prolate ellipsoidal micelles to large unilamellar vesicles. Also, increasing the concentration in the case of [Cmmor][Sal] resulted in a lower aggregation number.
合成了两种带有芳香族抗衡离子的吗啉鎓基表面活性离子液体（SAILs），即十二烷基甲基吗啉鎓水杨酸盐[Cmmor][Sal]和十二烷基甲基吗啉鎓3 - 羟基 - 2 - 萘酸盐[Cmmor][3 - - 2 - ]，并系统地研究了它们在水溶液中的聚集行为。采用电导率、小角中子散射（SANS）、表面张力（ST）和紫外 - 可见光谱测量来确定各种热力学、胶束和界面参数，如抗衡离子结合度（β）、临界胶束浓度（CMC）、每个分子的最小面积（）、表面过剩浓度（Γ）、吸附的标准吉布斯自由能（Δ）、聚集数（）、胶束化的标准吉布斯自由能（Δ）、胶束形成的标准焓（Δ）以及水溶液中胶束化的标准熵（Δ）。与传统的卤化SAILs如[Cmmor][Br]相比，引入芳香族抗衡离子显著有利于获得优异的胶束化性能。SANS分析表明，当抗衡离子从水杨酸盐变为3 - 羟基 - 2 - 萘酸盐时，结构从扁长椭球形胶束变为大的单层囊泡。此外，在[Cmmor][Sal]的情况下增加浓度会导致聚集数降低。
