摘要
报道了一种'线性-超支化'超分子聚合物的制备、自组装及其光响应性解组装过程.分别通过可控阴离子开环聚合(ROMBP)和原子转移自由基聚合(ATRP)的方法,制备了以β-环糊精为中心的超支化聚缩水甘油醚(CD-g-HPG)和一端带有偶氮苯基团的线性聚苯乙烯(AZO-PS).两者通过β-环糊精和偶氮苯基团之间的主客体识别作用形成'线性-超支化'超分子聚合物PS-b-HPG.该聚合物可以在水中自组装形成囊泡结构.通过紫外滴定法表征了CD-g-HPG和AZO-PS之间的主客体复合能力,通过SEM和TEM表征了组装体的形貌.最后基于偶氮苯在紫外光照射下发生顺反异构化的性质,用紫外光照射组装体成功实现了组装体的解组装.
Herein we reported the synthesis, self-assembly and light-responsive disassembly of a ＂linear-hyperbranched＂ supramolecular polymer. Firstly, a hyperbranched polymer CD-g-HPG composed of hyperbranched polyglycerol with a β-cyclodextrin group in the center was synthesized by ring-opening multibranching polymerization （ROMBP）. Secondly, a linear polymer AZO-PS composed of polystyrene with an azobenzene group at the end was synthesized via atom transfer radical polymerization （ATRP）. Then, the linear AZO-PS and hyperbranched CD-g-HPG were conjugated together through the specific CD/AZO host-guest interactions, leading to the formation of the ＂linear-hyperbranched＂ supramolecular polymer PS-b-HPG. This supramolecular polymer was amphiphilic and could self-assemble into vesicles in water. The host-guest complexation ability was characterized by UV-Vis titration. In the case of keeping the concentration of AZO-PSs unchanged, the absorption peak at 330 nm increased gradually with the addition of CD-g-HPGs, which supported the occurrence of com- plexation between β-CD groups in CD-g-HPGs and AZO groups in AZO-PSs. The host-guest CD/AZO complexation constant of 4.14× 10^4 M^-1 was calculated by the Benesi-Hildebrand plot. A Job plot was generated, from which it was determined that the binding stoichiometry between AZO-PS and CD-g-HPG is 1：1. The self-assemblies of the amphiphlic linear-hyperbranched supramolecular polymers were characterized by SEM and TEM. The SEM images showed that the self-assemblies were spherical particles, and the holes directly be seen in some particles indicated that they were vesicles or hollow spheres with a very thin wall thickness. The TEM images of self-assemblies stained with ruthenium tetroxide （RuO4） indicated that the spherical particles were vesicles according to a clear contrast difference between the inner pool and the outer thin wall. At last, we showed that the vesicles could disassemble under UV light due to the trans-to-cis isomerisation of the AZO groups.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2016年第5期415-421,共7页
Acta Chimica Sinica
基金
国家重点基础研究发展计划(973计划
No.2013CB834506)
国家杰出青年基金(No.21225420)
国家自然科学基金(Nos.21474062
91527304)资助~~
关键词
超分子聚合物
线性-超支化
主客体相互作用
自组装
光响应性
supramolecular polymers
linear-hyperbranched
host-guest interactions
self-assembly
light responsive
