期刊
JOURNAL OF MOLECULAR LIQUIDS
卷 332, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.molliq.2021.115722
关键词
Ionic liquids; Micelles; Neutron scattering; MD simulation; Lateral motion; Segmental dynamics; Water in hydration layer; Quasielastic neutron scattering
The study focuses on the structure and dynamics of an ionic liquid surfactant system, revealing that the alkyl chains are more ordered, hydration dynamics are slower, and lateral motion is faster in comparison to conventional surfactant micelles.
Ionic liquids have drawn vast attention due to their extraordinary physicochemical properties and their relevance in a wide range of applications. As a result of their inherent amphiphilic nature, many ionic liquids are emerging as novel surfactants, being referred to as surface active ionic liquids (SAILs). Under suitable conditions in aqueous solution, these SAILs self-assemble to form nanostructures such as micelles and vesicles. Here, we report on the structure and dynamics of one such SAIL micellar system, 1-Decyl-3-methylimidazolium Bromide (DMIMBr), as studied using fully atomistic molecular dynamics (MD) simulation and quasi-elastic neutron scattering (QENS). Results are compared with a conventional surfactant, dodecyltrimethylammonium bromide (DTAB) micelles. MD simulations showed that while the structure of the DMIMBr micelle is very similar to that of DTAB, the conformational flexibility of the alkyl chains is starkly different. The alkyl chains in the SAIL are more ordered, having fewer gauche defects. This is consistent with experimental results obtained using QENS which also showed slower alkyl chain segmental dynamics. MD results also show restricted dynamics of the hydration water in DMIMBr micelles, of a sub-diffusive nature, suggesting stronger affinity of water molecules to the imidazolium moiety. Thus the decreased flexibility in the alkyl chains could arise from the slower hydration dynamics. In contrast, the lateralmotion of the surfactant is found to be relatively faster inDMIMBr micelles than inDTAB micelles. The understanding gained fromthis study provides a microscopic insight about the dynamical aspects of SAIL micelles, which might be useful for related applications including micellar catalysis and nanoparticle synthesis. (C) 2021 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据