双重响应性POSS基嵌段共聚物的合成及其溶液自组装行为的研究

(厦门大学 材料学院,福建省防火阻燃材料重点实验室,福建 厦门 361005)

POSS基嵌段共聚物; pH响应性; 温度响应性

Synthesis of Double-responsive POSS-based Block Copolymer and Study on Its Self-assembly Behavior in Solution
SUN Xiaoqing,CAO Jie,LI Jilu,HE Kaiwei,XU Yiting*,DAI Lizong

(Key Laboratory of Fire Retardant Materials of Fujian Province,College of Materials,Xiamen University,Xiamen 361005,China)

POSS-based block copolymer; pH-responsive; temperature-responsive

DOI: 10.6043/j.issn.0438-0479.201706023

备注

以温度响应性N-异丙基丙烯酰胺(NIPAM)和pH响应性丙烯酸(AA)作为功能单体,与甲基丙烯酰氧丙基七异丁基笼形倍半硅氧烷(MAPOSS)通过可逆加成-断裂转移聚合法(reversible addition-fragmentation chain transfer polymerization,RAFT)共聚,合成具有双重响应性的多面体齐聚倍半硅氧烷(polyhedral oligomeric silsesquioxane,POSS)基嵌段共聚物PMAPOSS-b-(PNIPAM-co-PAA); 采用动态光散射(dynamic light scattering,DLS)、紫外-可见吸收光谱和荧光光谱等测试手段研究了POSS基嵌段共聚物的温度与pH响应行为.结果表明:嵌段共聚物胶束在外部环境pH变小时,粒径明显增大,而在较高pH下,胶束粒径保持稳定; 当外部环境温度小于低临界溶解温度(lower critical solution temperature,LCST)时,嵌段共聚物胶束粒径较大,当温度升高到LCST及以上时,嵌段共聚物胶束粒径变小; 对于包芘共聚物胶束,在酸性条件下芘能较快释放,且释放速度与疏水链段长短有关,而当包芘共聚物胶束所处环境温度高于LCST时也会导致芘的释放.

POSS-based block copolymers,PMAPOSS-b-(PNIPAM-co-PAA),with double reactivity were prepared via reversible addition-fragmentation chain transfer polymerization(RAFT)using methacrylate isobutyl polyhedral oligomericsilsesquioxane(MAPOSS),and temperature-responsive N-isopropyl acrylamide(NIPAM)and pH-responsive acrylic acid(AA)as functional monomers.And dynamic light scattering(DLS),UV-vis and fluorescence spectroscopies were used to study the temperature- and pH-responsive behaviors of POSS-based block copolymers.The results showed that when the pH was small,the particle size increased obviously,while at a higher pH,the micelle size was stable.When the temperature was lower than lower critical solution temperature(LCST),the PNIPAM segment was stretched and the particle size of the block copolymer micelle was larger.When the temperature was higher than LCST,the particle size of the block copolymer micelle became smaller.Under the acidic condition,pyrene in pyrene-copolymer micelles could be released in a very short time,and the release rate was related to the hydrophobic chain length.When the environmental temperature of pyrene-copolymer micelles was higher than LCST,pyrene could also be released.