Effect of Ionic Liquids on the Aggregation Behavior of PEO-PPO-PEO Block Copolymers in Aqueous Solution

Abstract

Effect of 1-butyl-3-methyl-imidazolium bromide (BmimBr) on the aggregation behavior of PEO-PPO-PEO Pluronic P104 aqueous solution was studied by Fourier transform infrared (FTIR) spectroscopy, freeze fracture transmission electron microscopy (FF-TEM), dynamic light scattering (DLS), and NMR spectroscopy. When the BmimBr concentration was below 1.232 mol/L, the critical micelle temperature (CMT) of Pluronic P104 remained constant, while the size of micelles increased with increasing the BmimBr concentration; above this concentration, the CMT of Pluronic P104 decreased abruptly, and bigger clusters of BmimBr were formed. The selective nuclear Overhauser effect (NOE) spectrum indicates that the PO block of the P104 interacts with the butyl group of the Bmim+ cation by hydrophobic interaction. It suggests that when the concentration of BmimBr is below 1.232 mol/L, there are P104 micelles in the aqueous solution with BmimBr embedding to the micellar core, while above this concentration, P104 micelles and BmimBr clusters coexist in the system.

Interaction between ionic liquid and zwitterionic surfactant: A comparative study of two ionic liquids with different anions

“…As far as IL-induced changes in micellar size are concerned, it is reported that addition of [bmim][Br] to aqueous solution of a block copolymer, PEO-PPO-PEO Pluronic P104, resulted in a dramatic increase in the effective diameter of the micelles formed by this nonionic copolymer [84]. However, our earlier reports indicate a decrease in the size of micellar aggregates upon addition of 2 wt% [bmim] [BF 4 ] to aqueous nonionic TX100 [52]; the addition of the same amount of this IL to aqueous anionic SDS resulted in a dramatic increase in micellar size [54].…”

Formation of micelles of Pluronic block copolymers in PEG 200

“…Micellar solutions show excellent properties in chemical reactions [1], drug delivery [2,3], and the synthesis of nanomaterials [4,5]. The study of the properties of micellar solutions has been an interesting topic for many years [6][7][8][9].…”

Supramolecular Structures in the Presence of Ionic Liquids

“…It is found that ILs acted as a metal salt at low concentrations and participated in the micellar phase with increasing [C 4 mim] [PF 6 ] which led to a considerable decrease in the microfluidity of SDS micelles (Behera & Pandey, 2007a, b). ILs also influence the aggregation behavior of Pluronic polymers (Dey et al, 2009;Zheng et al, 2007). Zheng et al The formation of liquid crystal in ILs was firstly reported by Evans and co-workers (Evans et al, 1983a) in 1983, which was formed by β,  γ-distearoylphosphotidylcholine (DSPC) in EAN.…”