光致驱动聚醚的主/侧链结构设计及光致形变性能调控

Backbone/Branched Chain Structure Tailoring and Photoinduced Deformability Controlling of Photodriven Polyethers

报道了一种通过开环聚合与点击化学侧基修饰制备的后功能化光敏性聚醚材料.以烯丙基缩水甘油醚(AGE)为前驱体,通过新戊酸铯催化可控阴离子开环聚合(ROP)获得聚烯丙基缩水甘油醚(PAGE),并通过巯基-烯(Thiol-ene)点击化学和酯化两步反应将光敏基团肉桂酰氯引入到PAGE侧链上,合成了具有光敏特性的聚醚.PAGE的主链长度与肉桂酰氯侧基接枝率可分别通过调控单体/引发剂比例与反应时间灵活调控.将所得侧链修饰后的PAGE预聚物进行光固化成型,获得的光敏性聚酯薄膜具有较低的玻璃化转变温度(T_(g)),同时可在365和254 nm波长紫外光照下发生可逆[2+2]环加成反应,展现出快速可逆的变形特征.本工作通过开环聚合与点击化学反应设计优化了聚醚主侧链结构,为拓宽光功能性聚醚的使用温度窗口、提升其光致变形灵敏度提供了思路,有望使所得材料进一步在药物可控释放、柔性智能机器人等领域得到更加广泛的应用.

A post-functionalized photosensitive polyether material prepared by ring-opening polymerization(ROP),as well as side group modification that conducted by“click chemistry”is reported in this work.Allyl glycidyl ether(AGE)was used as the precursor to prepare poly(allyl glycidyl ether)(PAGE)by anionic ring-opening polymerization under the catalysis of cesium pivalate.Then the photosensitive moieties of cinnamoyl chloride were introduced onto side chains of PAGE prepolymer by two-step reactions of thiol-ene“click chemistry”and esterification,aiming to prepare polyether with photosensitive properties.The main chain length of PAGE prepolymer and the grafting rate of cinnamoyl chloride side groups can be flexibly controlled by adjusting the monomer/initiator ratio and grafting reaction time,respectively.After casted and photocured,the photosensitive PAGE film possesses a low glass transition temperature(T_(g)),and exhibits rapid and reversible deformation characteristic undergoing a reversible[2+2]cycloaddition reaction triggered by ultraviolet light with a wavelength of 365 and 254 nm.From the aspect of designing and optimizing the polyether main chain/side branches structure via ring-opening polymerization and“click chemistry”reaction design,the results provide practical ideas for broadening the service temperature window of photo-functional polyether,and improving its photo-induced deformation sensitivity.The obtained polyether materials also show some potential applications in the fields of controlled drug release and flexible intelligent robots.