Stimuli‐Responsive Ionic Liquids and the Regulation of Aggregation Structure and Phase Behavior†

Abstract

Ionic liquids with stimuli‐responsive characteristics are an essential branch in the comprehensive ionic liquids' family, which can meet the controllable and reversible needs in practical applications with different stimulation means. In this review, we summarize the recent research progress of these stimuli‐responsive ionic liquids, mainly focusing on their chemical structures, properties, responsive mechanism, aggregation structures, and phase behaviors, which were driven by external stimuli, such as CO2, magnetism, light, temperature, redox, and pH. Then, the particular or potential applications of stimuli‐responsive ionic liquids are expounded in various fields of science, including catalytic reaction, extraction, separation, nanomaterial preparation, and gas absorption. In the end, the challenges and strategies of the subject are briefly presented. It is expected that this review will contribute to the rational design and applications of stimuli‐responsive ionic liquids in the future.

Microstructural probing of phosphonium-based ionic liquids on a gold electrode using colloid probe AFM

“…The observed stiffer ion layers in the longer-chain [P 6,6,6,14 ][BScB] suggest that this IL prefers to accumulate on the gold electrode surfaces to form a more ordered layering structure. This stiffer ordered ion structure is expected to favor the conductivity improvement, 53 and thus speed up the electrochemical response.…”

Novel Designed PEG‐Dicationic Imidazolium‐Based Ionic Liquids as Effective Plasticizers for Sustainable Polylactide

“…Ionic liquids (ILs) are remarkable chemical compounds, which are found to have wide applications in many areas including creating new polymer materials with unprecedented chemical and physical properties. [ 14‐18 ] Recently, ILs as promising plasticizers for brittle polymer have stimulated intensive research interest because of their highly tunable nature and exceptional properties, including low volatility, nonflammability, high‐temperature stability, etc . [ 19‐20 ] For example, ILs were investigated as “green” and nonvolatile plasticizers for several commercial polymers including polyamide (PA), poly(methyl methacrylate) (PMMA), poly(vinyl chloride) (PVC), etc .…”

Molecular Dynamics Simulation of the Influence of External Electric Fields on the Glass Transition Temperature of the Ionic Liquid 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide

“…In addition to studies about the effect of chemical structure on the glass transition of ILs, other environmental and external variables have been studied such as doping, mixing, confinement in chemical Recently, research has been extended to examine the impact of external stimuli such as EEFs on IL properties. 41,42 Accounting for the effect that external stimuli can have on the ordering of ILs in addition to the chemical structure of its constituting components is the next phase in the discipline of molecular engineering of ILs. 43 By tailoring the chemical structure of the IL to respond to certain external stimuli, differences in thermodynamic and transport properties induced by a change in structure and ordering can be leveraged to develop novel processes.…”