基于快速热释放功能的偶氮基光热材料  

Azo-based Photo-thermal Materials Based on Rapid Heat Release

作　　者：阎清海 冯奕钰[1] 封伟[1] Qing-hai Yan;Yi-yu Feng;Wei Feng(School of Materials Science and Engineering,Tianjin University,Tianjin 300072)

机构地区：[1]天津大学材料科学与工程学院

出　　处：《高分子学报》2019年第9期925-931,I0003,共8页Acta Polymerica Sinica

基　　金：国家重点基金(基金号2016YFA0202302);国家自然科学基金(基金号51573125,51573147)资助项目

摘　　要：针对传统的偶氮储热材料仅能吸收紫外光,并且高储能密度的储热材料诱导放热温度高,放热速率低的问题,通过分子设计,在偶氮苯中引入具有吸电子性的噻唑杂环,与具有推电子性的甲氧基形成推拉电子结构.推拉电子结构的杂环偶氮苯分子具有快速回复和吸收紫光的特点.同时以石墨烯为模板制备储热复合材料,增加了分子间相互作用,从而使材料的储热密度达到了89 Wh/kg,半衰期为10 h,输出功率具有890 W/kg.材料在435 nm波长处有最大的吸收强度,实现了对紫光区域的吸收.该储热材料在60和80℃的刺激下分别达到了2.6和3.8℃的温差.通过温度刺激,储热材料释放的热能够使2种热致变色颜料(62℃下发生红色→无色,82℃下发生蓝色→无色)分别在60和80℃环境下发生明显的消色,通过不同温度刺激产生不同温差使得热致变色颜料发生颜色改变,实现了放热的可视化.Azobenzene(Azo)can absorb specific wavelength light that makes a change from trans-state to cisstate structure.Energy storage can be achieved by the difference in energy levels between the two isomers,so Azo is often used as energy storage materials.The conventional Azo photo-thermal storage materials have problems of relying on the utilization of ultraviolet light,requiring a high temperature stimulation,and a low-rate heat release.Herein,by utilizing diazonium salt method to introduce thiazole and methoxy groups into Azo to form a push-pull electronic structure,thiazole-heterocyclic Azo(t-Azo-h)achieves fast heat release.The photo-thermal storage composite(t-Azo-h/rGO)is obtained through grafting azo monomers onto the surface of reduced graphene oxide(rGO).Due to the close accumulation of Azo units on the surface of rGO,t-Azo-h/rGO of graphene-templated assembly increases the intermolecular interaction,resulting in an energy storage density of 89 Wh/kg,a half-life of 10 h,and a high power density of 890 W/kg at a heating rate of 5℃/min.UV spectrum shows the maximum absorption intensity is at 435 nm,realizing absorption of the violet region because of molecular polarizability increased due to push-pull electronic properties.Red shift of spectral absorption broadens the use of sunlight.Owing to fast heat release,t-Azo-h/rGO reaches the temperature difference of 2.6℃ under 60℃ and 3.8℃ under 80℃,respectively.By designing thermochromic pigment in combination with photo-thermal film,the decoloration occurs in two thermochromic pigments(red→colorless at 62℃,blue→colorless at 82℃)due to the heat release of photo-thermal material under heat stimulation.The t-Azo-h/rGO with fast heat release achieves the thermal visualization by optimizing stimulus.By designing push-pull electronic structure,a kind of photothermal material with fast thermal output is obtained and photo-thermal material with rapid heat release could finish a higher power density output at low temperature than that of slow heat release.A

关 键 词：杂环 储热密度 功率密度 可视化 推拉电子结构 

分 类 号：G63[文化科学—教育学]