关键词: 离子液体, 偶氮苯, 光响应, 光致异构, 智能材料

Abstract: As a new type of smart material, stimuli-responsive materials have many important applications both in daily life and industrial production. However, such materials are just applied in limited fields because of high energy consumption, difficulty in precise control, and poor cycle reversibility. Azobenzene compound, where there is a photosensitive functional group, is relatively simple to be synthesized. And they are of good cycle reversibility, easy precise control, and relatively energy saving. The ionic liquid that exists as the liquid is a new type of material with low vapor pressure, good thermal stability, and low pollution to the environment. Moreover, the structure of ionic liquid is designable. Therefore, ionic liquid containing an azobenzene moiety is a new type of functional material that exhibits dual characteristics as light stimuli-responsiveness and ionic liquids. Taking full advantage of the photoisomerization which is induced by ultraviolet and visible light irradiation, the physical and chemical properties of such materials can be tuned. The issue of light stimuli-responsive ionic liquids containing azobenzene moieties has been a hot topic in recent years. This article reviewed and summarized recent studies on the properties and performance of ionic liquids containing azobenzene group upon UV and visible light irradiation, which was furtherly applied in the field of smart materials. Specifically, examples of recent applications of ionic liquids containing azobenzene group across a multitude of fields such as light-controlled conductivity, light-controlled self-assembly, light-controlled phase behavior, light-controlled CO2 capture and release as well as light response controllable viscoelasticity of ionic gel are all described in detail, and their future development also prospects in this work. Ionic liquids containing azobenzene moiety have unique advantages and are expected to provide new ideas for the development of smart materials and green chemistry under the background of sustainable development.

Key words: ionic liquid, azobenzene, light response, photo-induced isomerization, smart material