Micellization of long-chain ionic liquids in deep eutectic solvents

• Published in: Soft matter 2016-01, Vol.12 (24), p.5297-533
• Main Authors: Tan, Xiuniang, Zhang, Jianling, Luo, Tian, Sang, Xinxin, Liu, Chengcheng, Zhang, Bingxing, Peng, Li, Li, Wei, Han, Buxing
• Format: Article
• Language: English
• Subjects: Agglomeration; Chains; Chlorides; Eutectics; Formations; Ionic liquids; Nanocrystals; Solvents
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/c6sm00924g

The aggregation behavior of the ionic liquid (IL) 1-alkyl-3-methylimidazolium chloride with different alkyl chain lengths in a deep eutectic solvent (DES, composed of choline chloride and glycerol in a 1 : 2 mole ratio) was studied for the first time. The critical micellar concentration, micellar size and intermolecular interactions in IL/DES solutions were investigated by different techniques including the fluorescence probe technique, small angle X-ray scattering and Fourier transform infrared spectroscopy. The solvophobic effect dominates the micellization of C n mimCl in DES and the intermolecular hydrogen-bond interaction plays a positive role to promote micelle formation. The micellar solutions were utilized for the synthesis of the water-unstable metal-organic framework Cu 3 (BTC) 2 (BTC = 1,3,5-benzenetricarboxylate) at room temperature. X-Ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms confirm the formation of crystalline Cu 3 (BTC) 2 nanocrystals with mesoporous structures. The morphologies and porosity properties of Cu 3 (BTC) 2 nanocrystals can be modulated by varying the concentration of C n mimCl. The long-chain ionic liquid (1-alkyl-3-methylimidazolium chloride) can self-assemble into micelles in deep eutectic solvent (glyceline). This novel kind of micellar solution provides a facile, rapid, low-energy and environmentally benign route for the synthesis of water-sensitive metal-organic frameworks.