文献类型：期刊文献

英文题名：Self-assembly and multi-stimuli responsive behavior of PAA-b-PAzoMA-b-PNIPAM triblock copolymers

作者：Gao, Fei[1];Xing, Yaohui[1];Yao, Yuan[1];Sun, Liuying[1];Sun, Yao[1];He, Xiaohua[2];Lin, Shaoliang[1]

机构：[1]East China Univ Sci & Technol, Sch Mat Sci & Engn, Shanghai Key Lab Adv Polymer Mat, Key Lab Ultrafine Mat,Minist Educ, Shanghai 200237, Peoples R China;[2]East China Normal Univ, Dept Chem, Shanghai 200241, Peoples R China

年份：2017

卷号：8

期号：48

起止页码：7529

外文期刊名：POLYMER CHEMISTRY

收录：;EI(收录号：20175104561981);WOS:【SCI-EXPANDED(收录号:WOS:000417949500012)】；

基金：This work was supported by the National Natural Science Foundation of China (51622301, 51573046, and 51573088). Support from the Projects of Shanghai Municipality (14SG29 and 17JC400700) and the Fundamental Research Funds for the Central Universities (B14018 and WD1616010) is also appreciated.

语种：英文

外文关键词：Block copolymers - Azobenzene - Isomers - Acrylic monomers - Irradiation - Isomerization - Self assembly - Living polymerization

摘要：In this work, a triblock copolymer poly(acrylic acid)-block-poly[6-(4-methoxy-azobenzene-4'-oxy) hexyl-methacrylate]- block-poly(N-isopropylacrylamide) (PAA-b-PAzoMA-b-PNIPAM) containing pH, photo and temperature sensitive groups was synthesized through three-step RAFT polymerization. By tuning the solvents, the copolymer could self-assemble into spherical micelles or vesicles with multi-stimuli responsiveness. Either the micelles or the vesicles underwent obvious size decreases when the temperature was above the LCST of PNIPAM, and size increases when the pH value was below the pK(a) of PAA without obvious morphology changes. In addition, under UV irradiation, the micelles disrupted into much smaller particles whereas the vesicles transformed into micelles with an apparent size decrease on account of trans-to-cis isomerization of the azobenzene moieties. Upon irradiation by linear polarized light, the micelles were elongated into spindles and short rods. Furthermore, the photo-isomerization rate of the azobenzene moiety could be modulated by pH and temperature. The multi-stimuli responsive properties of PAA-b-PAzoMA-b-PNIPAM will further expand the potential application of azobenzene copolymers in smart materials.