Panda Somenath, Kundu Kaushik, Kiefer Johannes, Umapathy Siva, Gardas Ramesh L
Department of Chemistry , Indian Institute of Technology Madras , Chennai 600036 , India.
Department of Inorganic and Physical Chemistry , Indian Institute of Science , Bangalore 560012 , India.
J Phys Chem B. 2019 Apr 18;123(15):3359-3371. doi: 10.1021/acs.jpcb.9b01603. Epub 2019 Apr 9.
Despite the recent advancements in the field of deep eutectic solvents (DESs), their high viscosity often prevents practical applications. A versatile strategy to overcome this problem is either to add a co-solvent or to confine the DES inside a nanoscaled self-organized system. This work assesses the microstructures of a hydrated and nanoconfined DES comprising benzyltripropylammonium chloride [BTPA]Cl and ethylene glycol (EG). They act as a hydrogen-bond acceptor and a donor, respectively. The hydrogen bonding between [BTPA]Cl and EG in the DES (i.e., BTEG) and the molecular states of water in the hydrated BTEG were studied by Raman spectroscopy. The results show different hydrogen-bonding associations between water-water and water-BTEG or EG molecules. In addition, we investigated the confinement effects of BTEG in a Polysorbate 80 (Tween-80)/cyclohexane reverse micellar (RM) system. The results are compared with those of an ionic liquid-encapsulated RM system. The formation, bonding characteristics, and thermal stability of the RM droplets were studied by solubilization, dynamic light scattering, rheology, and Raman spectroscopy experiments. Furthermore, it is shown that hydrogen bonding between the DES and the surfactant leads to a stable RM system. Interestingly, the viscosity of the RM system is significantly lower than that of the neat DES suggesting that DESs have a much wider practical applicability in the form of RMs.
尽管近年来在深共熔溶剂（DESs）领域取得了进展，但其高粘度常常阻碍实际应用。克服这一问题的通用策略是添加共溶剂或将DES限制在纳米级自组装系统中。这项工作评估了一种由苄基三丙基氯化铵[BTPA]Cl和乙二醇（EG）组成的水合纳米受限DES的微观结构。它们分别作为氢键受体和供体。通过拉曼光谱研究了DES（即BTEG）中[BTPA]Cl与EG之间的氢键以及水合BTEG中水的分子状态。结果表明，水-水、水-BTEG或EG分子之间存在不同的氢键缔合。此外，我们研究了BTEG在聚山梨醇酯80（吐温80）/环己烷反胶束（RM）体系中的限制效应。将结果与离子液体包封的RM体系进行了比较。通过增溶、动态光散射、流变学和拉曼光谱实验研究了RM液滴的形成、键合特性和热稳定性。此外，研究表明DES与表面活性剂之间的氢键导致了稳定的RM体系。有趣的是，RM体系的粘度明显低于纯DES，这表明DES以RM的形式具有更广泛的实际应用前景。
