Interaction of ionic liquid with water with variation of water content in 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6])/TX-100/water ternary microemulsions monitored by solvent and rotational relaxation of coumarin 153 and coumarin 490

2007 ◽  
Vol 126 (22) ◽  
pp. 224512 ◽  
Author(s):  
Debabrata Seth ◽  
Anjan Chakraborty ◽  
Palash Setua ◽  
Nilmoni Sarkar
Keyword(s):  
Ionic Liquid ◽  
Water Content ◽  
Rotational Relaxation ◽  
Coumarin 153

scholarly journals Tuning Water Networks via Ionic Liquid/Water Mixtures

2020 ◽  
Vol 21 (2) ◽  
pp. 403 ◽  
Author(s):  
Archana Verma ◽  
John P. Stoppelman ◽  
Jesse G. McDaniel
Keyword(s):  
Ionic Liquid ◽  
Water Content ◽  
Relaxation Times ◽  
Water Structure ◽  
Lyotropic Liquid Crystals ◽  
Rotational Relaxation ◽  
Membrane Materials ◽  
Water Fraction ◽  
Pairwise Correlation ◽  
Dynamics Simulations

Water in nanoconfinement is ubiquitous in biological systems and membrane materials, with altered properties that significantly influence the surrounding system. In this work, we show how ionic liquid (IL)/water mixtures can be tuned to create water environments that resemble nanoconfined systems. We utilize molecular dynamics simulations employing ab initio force fields to extensively characterize the water structure within five different IL/water mixtures: [BMIM + ][BF 4 − ], [BMIM + ][PF 6 − ], [BMIM + ][OTf − ], [BMIM + ][NO 3 − ] and [BMIM + ][TFSI − ] ILs at varying water fraction. We characterize water clustering, hydrogen bonding, water orientation, pairwise correlation functions and percolation networks as a function of water content and IL type. The nature of the water nanostructure is significantly tuned by changing the hydrophobicity of the IL and sensitively depends on water content. In hydrophobic ILs such as [BMIM + ][PF 6 − ], significant water clustering leads to dynamic formation of water pockets that can appear similar to those formed within reverse micelles. Furthermore, rotational relaxation times of water molecules in supersaturated hydrophobic IL/water mixtures indicate the close-connection with nanoconfined systems, as they are quantitatively similar to water relaxation in previously characterized lyotropic liquid crystals. We expect that this physical insight will lead to better design principles for incorporation of ILs into membrane materials to tune water nanostructure.

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