54004-47-6Relevant articles and documents
Photoresponsive Self-Assembly of Surface Active Ionic Liquid
Wu, Aoli,Lu, Fei,Sun, Panpan,Gao, Xinpei,Shi, Lijuan,Zheng, Liqiang
, p. 8163 - 8170 (2016)
A novel photoresponsive surface active ionic liquid (SAIL) 1-(4-methyl azobenzene)-3-tetradecylimidazolium bromide ([C14mimAzo]Br) with azobenzene located in the headgroup was designed. Reversible vesicle formation and rupture can be finely controlled by photostimuli without any additives in the aqueous solution of the single-tailed ionic liquid. The photoisomerization of the azobenzene derivative was investigated by 1H NMR and UV-vis spectroscopy. Density functional theory (DFT) calculations further demonstrate that trans-[C14mimAzo]Br has less negative interaction energy, which is beneficial to aggregate formation in water. The incorporation of trans-azobenzene group increases the hydrophobicity of the headgroup and reduces the electrostatic repulsion by delocalization of charge, which are beneficial to the formation of vesicles. However, the bend of cis-azobenzene makes the cis-isomers have no ability to accumulate tightly, which induces the rupture of vesicles. Our work paves a convenient way to achieve controlled topologies and self-assembly of single SAIL.
Aggregation behavior of zwitterionic surface active ionic liquids with different counterions, cations, and alkyl chains
Sun, Panpan,Shi, Lijuan,Lu, Fei,Zheng, Liqiang
, p. 27370 - 27377 (2016/03/30)
A group of zwitterionic surface active ionic liquids (SAILs) with different counterions, cations and alkyl chains, 3-(1-alkyl-3-imidazolio)propanesulfonate β-naphthalene sulfonate, (CnIPS-Nsa, n = 12, 14), 3-(1-dodecyl-3-imidazolio)propanesulfonate benzenesulfonate (C12IPS-Bsa), and dodecyl-N,N-dimethylammonio-3-propane sulfonate β-naphthalene sulfonate (SB-12-Nsa), were synthesized. Their aggregation behaviors in aqueous solutions were systematically investigated by surface tension, dynamic light scattering (DLS) and 1H NMR spectroscopy. Surface tension and DLS results illustrated that the surface properties, micelle size, and micellization behavior of zwitterionic SAILs in aqueous solutions are significantly affected by the anion type, anionic structure and the hydrophobicity of the alkyl chain. The SAILs with more hydrophobic anions and long alkyl chains are expected to favor the micellization. The steric hindrance and hydrophobicity of the cations, as well as the binding strength of the cations with the anions, also play important roles in the aggregation of zwitterionic SAILs. Additionally, the micelle formation mechanism was acquired by detailed analysis of the 1H NMR spectra. The existence of π-π stacking between imidazolium and counterions was proved. The enhanced π-π stacking and hydrophobic effect of Nsa- can promote the aggregation of zwitterionic SAILs. Density functional theory (DFT) calculations illustrated that the negative interaction energy of the complexes were C12IPS-Bsa/H2O > SB-12-Nsa/H2O > C12IPS-Nsa/H2O > C14IPS-Nsa/H2O. It is more difficult to form micelles in complexes with more negative interaction energy. The counterion electronegativity of Nsa- is smaller than that of Bsa-, which favors the formation of micelles.
A Comprehensive Study on the Synthesis and Micellization of Disymmetric Gemini Imidazolium Surfactants
Zhao, Xiaohui,An, Dong,Ye, Zhiwen
, p. 681 - 691 (2016/07/06)
Two groups of disymmetric Gemini imidazolium surfactants, [C14C4Cmim]Br2 (m?=?10, 12, 14) and [CmC4Cnim]Br2 (m?+?n?=?24, m?=?12, 14, 16, 18) surfactants, were synthesized and their structures were confirmed by 1H NMR and ESI–MS spectroscopy. Their adsorption at the air/water interface, thermodynamic parameters and aggregation behavior were explored by means of surface tension, electrical conductivity and steady-state fluorescence. A series of surface activity parameters, including cmc, γcmc, πcmc, pC20, cmc/C20, Γmax and Amin, were obtained from surface tension measurements. The results revealed that the overall hydrophobic chain length (Nc) for [C14C4Cmim]Br2 and the disymmetry (m/n) for [CmC4Cnim]Br2 had a significant effect on the surface activity. The cmc values decreased with an increase of Nc or m/n. The thermodynamic parameters of micellization (ΔGm θ, ΔHm θ, ΔSm θ) derived from the electrical conductivity indicated that the micellization process of [C14C4Cmim]Br2 and [CmC4Cnim]Br2 was entropy-driven at different temperatures, but the contribution of ΔHm θ to ΔGm θ was enhanced by increasing Nc or m/n. The micropolarity and micellar aggregation number (Nagg) were estimated by steady-state fluorescence measurements. The results showed that the surfactant with higher Nc or m/n can form larger micelles, due to a tighter micellar structure.